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Roux-en-Y Gastric Bypass Is Associated With Early Increased Risk Factors for Development of Calcium Oxalate Nephrolithiasis
Abstract
Patients treated for obesity with jejunoileal bypass (JIB) experienced a marked increased risk of hyperoxaluria, nephrolithiasis, and oxalate nephropathy developing. Jejunoileal bypass has been abandoned and replaced with other options, including Roux-en-Y gastric bypass (RYGB). Changes in urinary lithogenic risk factors after RYGB are currently unknown. Our purpose was to determine whether RYGB is associated with elevated risk of developing calcium oxalate stone formation through increased urinary oxalate excretion and relative supersaturation of calcium oxalate.
A prospective longitudinal cohort study of 24 morbidly obese adults (9 men and 15 women) recruited from a university-based bariatric surgery clinic scheduled to undergo RYGB between December 2005 and April 2007. Patients provided 24-hour urine collections for analysis 7 days before and 90 days after operation. Primary outcomes were changes in 24-hour urinary oxalate excretion and relative supersaturation of calcium oxalate from baseline to 3 months post-RYGB.
Compared with their baseline, patients undergoing RYGB had increased urinary oxalate excretion (31 +/- 10 mg/d versus 41 +/- 18 mg/d; p = 0.026) and relative supersaturation of calcium oxalate (1.73 +/- 0.81 versus 3.47 +/- 2.59; p = 0.030) 3 months post-RYGB in six patients (25%). De novo hyperoxaluria developed. There were no preoperative patient characteristics predictive of development of de novo hyperoxaluria or the magnitude of change of daily oxalate excretion.
This prospective study indicates that RYGB is associated with an earlier increase in urinary oxalate excretion and relative supersaturation of calcium oxalate than previously reported. Additional studies are needed to determine longterm post-RYGB changes in urinary oxalate excretion and identify patients that might be at risk for hyperoxaluria developing.
... A high incidence of hyperoxaluria has been reported among 2/3 of patients with kidney stones who have undergone RYGB [54][55][56][57][58][59]. The onset of development of hyperoxaluria varies and may occur either early or late following bariatric surgery, depending on the type of surgical procedure, the differences in dietary intake and the patient's health status [57,58]. ...
... A high incidence of hyperoxaluria has been reported among 2/3 of patients with kidney stones who have undergone RYGB [54][55][56][57][58][59]. The onset of development of hyperoxaluria varies and may occur either early or late following bariatric surgery, depending on the type of surgical procedure, the differences in dietary intake and the patient's health status [57,58]. However, urinary oxalate in the MN cohort was shown to increase over time in all patients following RYGB, with a more significant rise in those who developed kidney stones [51]. ...
... Hypocitraturia commonly occurs, but not for all patients following RYGB [54][55][56][57]59]. The prevalence varies from 24 to 63% [36,56,58,62]. ...
The impact of bariatric surgery on cardiovascular and diabetic complications associated with an improvement in survival has overshadowed the adverse skeletal health and development of kidney stone disease in this population. All longitudinal based studies in the literature reporting the incidence of bone fractures or kidney stones following bariatric surgery were reviewed. Moreover, all publications over the past decade which assessed changes in bone mineral density, bone quality, or explored underlying pathophysiologic mechanisms of bone and kidney stone disease were carefully reviewed. This review provides sufficient data to support that osteoporotic fractures and kidney stone disease are associated with Roux-en-Y gastric bypass surgery. However, due to the limited data available to date, no definitive conclusion could yet be drawn whether sleeve gastrectomy or adjustable gastric banding is associated with bone fractures and kidney stones. Bariatric surgery has emerged as the most effective and sustained treatment for weight reduction. This treatment modality has been recognized to diminish the risk of cardiovascular morbidity and mortality and ameliorate diabetes mellitus complications. The derangement in mineral metabolism has emerged as a major complication following bariatric surgery.
... Nephrolithiasis has emerged as a potential outcome after bariatric surgery (BS) (1,2), occurring in up to 7.6% of bariatric patients in a 5-year period, which represents almost a two-fold increased risk compared with obese controls (3). Several recent studies demonstrated that urinary abnormalities, such as low urine volume, hypocitraturia, and more commonly, hyperoxaluria, may predispose bariatric patients to nephrolithiasis (4)(5)(6)(7)(8)(9)(10)(11)(12). Hyperoxaluria is the most frequent lithogenic factor detected in the majority of studies, with prevalence rates between 29% and 74% (4)(5)(6)(7)(8)(9)(10)(11)(12) and time to onset of 3-24 months after the procedure (8,9). ...
... Several recent studies demonstrated that urinary abnormalities, such as low urine volume, hypocitraturia, and more commonly, hyperoxaluria, may predispose bariatric patients to nephrolithiasis (4)(5)(6)(7)(8)(9)(10)(11)(12). Hyperoxaluria is the most frequent lithogenic factor detected in the majority of studies, with prevalence rates between 29% and 74% (4)(5)(6)(7)(8)(9)(10)(11)(12) and time to onset of 3-24 months after the procedure (8,9). The potential underlying mechanisms for hyperoxaluria have not yet been determined, but some degree of fat malabsorption is speculated to play a role through the binding of fatty acids to calcium, thereby inhibiting the formation of poorly soluble, nonabsorbable calcium oxalate in the intestinal lumen (11,13). ...
... Several recent studies demonstrated that urinary abnormalities, such as low urine volume, hypocitraturia, and more commonly, hyperoxaluria, may predispose bariatric patients to nephrolithiasis (4)(5)(6)(7)(8)(9)(10)(11)(12). Hyperoxaluria is the most frequent lithogenic factor detected in the majority of studies, with prevalence rates between 29% and 74% (4)(5)(6)(7)(8)(9)(10)(11)(12) and time to onset of 3-24 months after the procedure (8,9). The potential underlying mechanisms for hyperoxaluria have not yet been determined, but some degree of fat malabsorption is speculated to play a role through the binding of fatty acids to calcium, thereby inhibiting the formation of poorly soluble, nonabsorbable calcium oxalate in the intestinal lumen (11,13). ...
Background and objectives:
Bariatric surgery (BS) may be associated with increased oxalate excretion and a higher risk of nephrolithiasis. This study aimed to investigate urinary abnormalities and responses to an acute oxalate load as an indirect assessment of the intestinal absorption of oxalate in this population.
Design, setting, participants, & measurements:
Twenty-four-hour urine specimens were collected from 61 patients a median of 48 months after BS (post-BS) as well as from 30 morbidly obese (MO) participants; dietary information was obtained through 24-hour food recalls. An oral oxalate load test (OLT), consisting of 2-hour urine samples after overnight fasting and 2, 4, and 6 hours after consuming 375 mg of oxalate (spinach juice), was performed on 21 MO and 22 post-BS patients 12 months after BS. Ten post-BS patients also underwent OLT before surgery (pre-BS).
Results:
There was a higher percentage of low urinary volume (<1.5 L/d) in post-BS versus MO (P<0.001). Hypocitraturia and hyperoxaluria (P=0.13 and P=0.36, respectively) were more frequent in BS versus MO patients. The OLT showed intragroup (P<0.001 for all periods versus baseline) and intergroup differences (P<0.001 for post-BS versus MO; P=0.03 for post-BS versus pre-BS). The total mean increment in oxaluria after 6 hours of load, expressed as area under the curve, was higher in both post-BS versus MO and in post-BS versus pre-BS participants (P<0.001 for both).
Conclusions:
The mean oxaluric response to an oxalate load is markedly elevated in post-bariatric surgery patients, suggesting that increased intestinal absorption of dietary oxalate is a predisposing mechanism for enteric hyperoxaluria.
... Nutrients 2020, 12, 1442 2 of 15 certainly the case in patients that have undergone BS and represents the most frequent metabolic disturbance detected among them, with prevalence rates ranging from 29% to around 67% at 3 months and 2 years after BS [8][9][10][11]. A recent meta-analysis has demonstrated a 36.4% increase in urinary oxalate levels after BS considering the 24-h urine profile from 277 patients belonging to six prospective studies after almost 1 year of RYGB [12]. ...
... The underlying mechanisms for an increasing urinary oxalate in post-BS patients have not been completely elucidated but may be accounted for dietary factors, intestinal fat malabsorption, alterations in gut microbiota, and/or changes in the intestinal oxalate transport [13], as hypothesized in Figure 1 below: Nutrients 2020, 12, x FOR PEER REVIEW 2 of 16 Secondary hyperoxaluria is certainly the case in patients that have undergone BS and represents the most frequent metabolic disturbance detected among them, with prevalence rates ranging from 29% to around 67% at 3 months and 2 years after BS [8][9][10][11]. A recent meta-analysis has demonstrated a 36.4% increase in urinary oxalate levels after BS considering the 24-hour urine profile from 277 patients belonging to six prospective studies after almost 1 year of RYGB [12]. ...
Bariatric surgery (BS) is one of the most common and efficient surgical procedures for sustained weight loss but is associated with long-term complications such as nutritional deficiencies, biliary lithiasis, disturbances in bone and mineral metabolism and an increased risk of nephrolithiasis, attributed to urinary metabolic changes resultant from low urinary volume, hypocitraturia and hyperoxaluria. The underlying mechanisms responsible for hyperoxaluria, the most common among all metabolic disturbances, may comprise increased intestinal oxalate absorption consequent to decreased calcium intake or increased dietary oxalate, changes in the gut microbiota, fat malabsorption and altered intestinal oxalate transport. In the current review, the authors present a mechanistic overview of changes found after BS and propose dietary recommendations to prevent the risk of urinary stone formation, focusing on the role of dietary oxalate, calcium, citrate, potassium, protein, fat, sodium, probiotics, vitamins D, C, B6 and the consumption of fluids.
... A small cross-sectional analysis of patients from the same cohort before and 12 months after a RYGB showed that hyperoxaluria and substantial increases in urinary CaOX supersaturation occurred in more than half of the previously normo-oxaluric patients [24]. The first prospective longitudinal study on 24 morbidly obese adults after the RYGB procedure [29] reported increases in urinary oxalate excretion rates and relative supersaturations of CaOx by 90 days after surgery. It was concluded that this early increase in urinary oxalate excretion could herald the onset of a clinically significant hyperoxaluric state [29]. ...
... The first prospective longitudinal study on 24 morbidly obese adults after the RYGB procedure [29] reported increases in urinary oxalate excretion rates and relative supersaturations of CaOx by 90 days after surgery. It was concluded that this early increase in urinary oxalate excretion could herald the onset of a clinically significant hyperoxaluric state [29]. To study the prevalence of hyperoxaluria after bariatric surgery, Patel et al. [30] screened 58 patients (52 with the RYGB procedure) and found hyperoxaluria (defined as a urinary oxalate excretion rate of >500 lmol/day) in three-quarters and profound hyperoxaluria (>1100 lmol/day) in a quarter of the patients [30]. ...
To give a comprehensive and focused overview on the current knowledge of the causal relations of metabolic syndrome and/or central obesity with kidney stone formation.Methods
Previous reports were reviewed using PubMed, with a strict focus on the keywords (single or combinations thereof): urolithiasis, nephrolithiasis, kidney stones, obesity, metabolic syndrome, bariatric surgery, calcium oxalate stones, hyperoxaluria, insulin resistance, uric acid stones, acid–base metabolism.ResultsObesity (a body mass index, BMI, of >30 kg/m2) affects 10–27% of men and up to 38% of women in European countries. Worldwide, >300 million people are estimated to be obese. Epidemiologically, a greater BMI, greater weight, larger waist circumference and major weight gain are independently associated with an increased risk of renal stone formation, both for calcium oxalate and uric acid stone disease.Conclusions
There are two distinct metabolic conditions accounting for kidney stone formation in patients with metabolic syndrome/central obesity. (i) Abdominal obesity predisposes to insulin resistance, which at the renal level causes reduced urinary ammonium excretion and thus a low urinary pH; the consequence is a greater risk of uric acid stone formation. (ii) Bariatric surgery, the only intervention that facilitates significant weight loss in morbidly obese people, carries a greater risk of calcium oxalate nephrolithiasis. The underlying pathophysiological mechanisms are profound enteric hyperoxaluria due to intestinal binding of calcium by malabsorbed fatty acids, and severe hypocitraturia due to soft or watery stools, which lead to chronic bicarbonate losses and intracellular metabolic acidosis.
... [4][5][6] RYGB increases urinary oxalate excretion and decreases urinary citrate, conditions commonly associated with the development of calcium oxalate stones. [7][8][9] Indeed, calcium oxalate stones comprise 75% to 80% of all stones in RYGB patients, implicating hyperoxaluria in the pathogenesis of urolithiasis. For this reason, calcium and vitamin D supplementation are routinely prescribed post-RYGB to reduce oxalate absorption from the gastrointestinal tract. ...
... While several studies have examined urinary parameters postoperatively, few have assessed the incidence of stone formation post-RYGB. [7][8][9] The first large scale study was conducted by Matlaga and colleagues. They examined urolithiasis within the first 4 years following RYGB surgery. ...
Introduction:
The risk of urolithiasis post-Roux-en-Y gastric bypass (RYGB) surgery is higher when compared to the general population. Calcium and vitamin D supplementation is routinely prescribed to these patients, yet compliance with these supplements is unknown. The aim of this study was to assess the incidence of symptomatic de novo urolithiasis post-RYGB and compliance with calcium and vitamin D supplementation.
Methods:
A standardized telephone questionnaire was administered to patients who underwent RYGB between 1996 and 2011. Personal and medical histories were obtained with emphasis on episodes of symptomatic urolithiasis and calcium and vitamin D supplementation.
Results:
The response rate was 48% with 478 patients completing the telephone questionnaire. After a mean follow-up of 7.0 years (range: 1-15), the incidence of post-RYGB symptomatic urolithiasis was 7.3%, while the rate of de novo symptomatic urolithiasis was 5%. The overall median time to present with symptomatic urolithiasis was 3.1 years, with 3.3 years for de novo stone-formers, and 2.0 years for recurrent stone-formers (p = 0.38). In de novo stone-formers, 33% presented with symptomatic urolithiasis 4 to 14 years postoperatively. Compliance with calcium and vitamin D supplementation was 56% and 51%, respectively.
Conclusions:
Despite recall bias and lack of confirmatory imaging studies, a high postoperative incidence of symptomatic urolithiasis was found in a large sample of post-RYGB patients. A third of patients with de novo stones, presented with symptomatic urolithiasis 4 to 14 years postoperatively. Compliance with postoperative calcium and vitamin D supplementation was poor and needs improvement.
... Histori-cally the RYGB has been the preferred intervention compared to GB. 6 However, evidence suggests an unintended consequence of the RYGB is hyperoxaluria and the increased potential for urolithiasis. [7][8][9][10][11][12][13][14][15] While obesity itself is associated with urolithiasis, the surgical treatment for obesity may, in contrast to its effect on other comorbidities, increase risk. 16 In those with no prior urolithiasis Patel et al found higher urinary oxalate in patients 1 year after RYGB compared to normal and stone forming cohorts. ...
... 8 Using preoperative and postoperative urinary measures Duffey et al found increased urinary oxalate in the early months following RYGB. 9 Matlaga et al recently reported increased stone incidence after RYGB, 10 confirming a prior report by Durrani et al. 11 Table 1 presents data illustrating preoperative and postoperative urine parameters associated with renal stones. ...
... Excessive hepatic synthesis of endogenous calcium due to different mutations is the hallmark of primary hyperoxaluria. Secondary hyperoxaluria is the most frequent metabolic abnormality among persons who have had MBS, with rates of incidence between 29% and approximately 67%, at three months and two years after MBS [185]. ...
Metabolic and bariatric surgery (MBS) is an effective intervention for patients with severe obesity and metabolic comorbidities, particularly when non-surgical weight loss methods prove insufficient. MBS has shown significant potential for improving quality of life and metabolic health outcomes in individuals with obesity, yet it carries inherent risks. Although these procedures offer a multifaceted approach to obesity treatment and its clinical advantages are well-documented, the limited understanding of its long-term outcomes and the role of multidisciplinary care pose challenges. With an emphasis on quality-of-life enhancements and the handling of postoperative difficulties, the present narrative review seeks to compile the most recent findings on MBS while emphasizing the value of an integrated approach to maximize patient outcomes. Effective MBS and patients’ management require a collaborative team approach, involving surgeons, dietitians, psychologists, pharmacists, and other healthcare providers to address not only physiological but also psychosocial patient needs. Comparative studies demonstrate the efficacy of various MBS methods, including Roux-en-Y gastric bypass and laparoscopic sleeve gastrectomy that may considerably decrease morbidity and mortality in individuals with obesity. Future studies should target long-term patient treatment, and decision making should be aided by knowledge of obesity, comorbidity recurrence rates, and permanence of benefits.
... After MBS, for example, patients have an increased risk of developing such conditions as gallstones, 117-120 gout, [121][122][123][124] and nephrolithiasis. [125][126][127][128] Nutritional deficits also may develop, some of them potentially catastrophic, including but not limited to central and peripheral nervous system disorders, 129,130 severe protein malnutrition, 62,131 osteoporosis and osteomalacia secondary to both rapid weight loss and vitamin D deficiency, [132][133][134][135] iron-deficiency anemia, 136,137 and immunocompromise. 138 Such deficiencies have been documented to occur in as many 139,140 Consequently, besides monitoring, postoperative follow-up needs to include ensuring that patients adhere to nutritional guidelines and to taking vitamin and mineral supplements, as prescribed. ...
... Few studies show an increase in urinary oxalate excretion after RYGB [8]. In our case, urinary oxalate was normal. ...
Oxalate nephropathy is a rare cause of kidney failure. Roux-en-Y gastric bypass surgery is a technique used for surgical treatment of obesity as well as for the treatment of gastric carcinoma. We report the case of a 46-year-old male who was admitted to the nephrology department due to kidney dysfunction eight months after bariatric surgery.
... 4 However, bariatric surgery has complications, such as secondary hyperoxaluria, the most prevalent metabolic anomaly discovered in these individuals, with prevalence rates ranging from 29% to 67%. [5][6][7] Oxalate is an organic acid in many plant-based foods (leafy green vegetables) and plant-based products (chocolate, peanut butter). It is a result of human liver metabolism produced from various precursors. ...
The current study is important in informing clinicians about the possibility of concurrent oxalate nephropathy caused by Roux‐en‐Y gastric bypass, high oxalate materials, and high‐dose vitamin C intake for COVID‐19 prevention.
... Our initial search produced 106 articles [12, 20•, 21-29, 30•], from which seven met criteria for inclusion in final analysis (Tables 1 and 2). There were five prospective case studies [12,[23][24][25][26], one case-control study [27], and one retrospective cohort study [28]. There were a total of 2498 participants who underwent GI surgery, with mean age of participants of 46.75 years (range: 21-66 years). ...
Purpose of Review
The association of kidney stone disease (KSD) and gastrointestinal (GI) surgery has been well established. With a rising obesity crisis, we wanted to see the correlation of urinary composition in patients undergoing bariatric surgery and their risk of KSD. The objective of this paper is to perform a systematic review and meta-analysis of literature to evaluate the changes in urinary composition and risk of KSD following bariatric surgery.
Recent Findings
A total of seven studies (2498 patients) underwent bariatric surgery with a mean age of 46.7 years and a male:female ratio of 1:3. The most popular bariatric surgery was the Roux-en-Y procedure. Meta-analysis of the studies showed that significant decrease in urinary calcium, citrate, and urate, and increase in urinary oxalate. There was also a nonsignificant volume reduction in the post-operative cohort. The decrease in urinary citrate and increase in urinary oxalate are both predisposing factors of stone formation.
Summary
There is strong evidence that bariatric surgery results in significant changes in urine composition in keeping with the increased risk of developing KSD. This identifies useful therapeutic targets in the prophylactic management of patients who have undergone bariatric surgery.
... This compares to 116 kcal or 4.4% in a sample of healthy people (92). Further indications that fat malabsorption cannot be overlooked is shown in the increased number of reports of kidney stone formation after RYGB (93)(94)(95)(96)(97)(98)(99)(100)(101), a mechanism that is well known from research on inflammatory bowel diseases (102). The treatment of oxalate stones includes a fat-reduced diet (102), reduced intake of foods rich in oxalate, increased calcium intake and manipulation of GI flora by using probiotics (103). ...
... Among the metabolic disturbances found after BS, increased oxalate (Ox) excretion is the most common one [1,2,5]. A poor calcium diet providing less calcium and decreasing the formation of non-absorbable calcium oxalate (CaOx) complexes in the intestinal lumen leads to freer Ox for absorption [6]. ...
Background:
Bariatric surgery is associated with hyperoxaluria hence predisposing to nephrolithiasis. The present study aimed to investigate the underlying mechanisms contributing to increased urinary oxalate in a mini-gastric bypass (MGB) surgery model in rats under different dietary conditions. The expression of intestinal oxalate transporters was also evaluated.
Methods:
Male rats underwent MGB (n = 21) or Sham procedure (n = 21) and after recovery were fed a standard or high-fat diet with or without oxalate for 8 weeks. Stool and urine were collected before surgery (baseline) and at the end of protocol (final), when intestinal fragments were harvested for expression of Slc26a3 and Slc26a6 oxalate transporters.
Results:
MGB groups fed with fat, irrespective of oxalate supplementation, presented steatorrhea. In MGB animals fed with fat and oxalate (Fat + Ox), final values of urinary oxalate and calcium oxalate supersaturation risk were markedly and significantly increased versus baseline or Sham animals under the same diet, as well as MGB groups under other diets. Slc26a3 was decreased in biliopancreatic limbs of MGB rats, probably reflecting a physiological adaptation to the restriction of food passage. Slc26a6 was not altered in any harvested intestinal fragment.
Conclusions:
A high-fat and oxalate diet induced hyperoxaluria and elevation in calcium oxalate supersaturation risk in a MGB rat model. The presence of fat malabsorption and increased dietary oxalate absorption, but not modifications of Slc26a3 and Slc26a6 oxalate transporters, accounted for these findings, suggesting that bariatric patients may benefit from a low-fat and low-oxalate diet.
... The pathogenesis of hyperoxaluria after RYGB is not completely understood, but the length of the common channel is Although RYGB operation with a Roux limb of <150 cm in length is generally believed not to cause fat malabsorption, data suggest that hyperoxaluria may indeed occur, and represent a risk for calcium oxalate nephrolithiasis [1]. Some earlier studies of patients with inflammatory bowel disease correlate the degree of hyperoxaluria with the degree of steatorrhea; this pathogenesis might explain why patients who have had distal RYGB (through creation of a longer Roux limb and subsequently shorter common channel for nutrient absorption) can be at higher risk for developing calcium oxalate kidney stones compared with standard RYGB patients [8]. ...
Roux-en-y-gastric bypass (RYGB) is the most commonly performed bariatric procedure worldwide which is taking the lead in resolving of comorbid conditions. Short- and long-term complications of RYGB procedure have been recognized, including osteopenia, osteomalacia and more rarely neurological disorders. Oxalate nephropathy is a complication of RYGB that has been described earlier in the literature and may end with renal failure and dialysis if not recognized and treated early. The etiology of this phenomenon is still unclear, but the length of common limb remains the theory that mostly contributed to its development. We believe that this limb should be more than 100 cm to prevent severe malabsorption. Here, we report a reversible case of oxalate nephropathy 3 months after RYGB in a 51-year-old patient.
... Hyperoxaluria is common after RYGB, but the incidence of renal calculi is much lower than after jejunal-ileal bypass (JIB) [198][199][200]. Comparison with the JIB is important because the incidence as well as the potential mechanisms may be different after RYGB. ...
Various bariatric surgical procedures are effective at improving health in patients with obesity associated co-morbidities, but the aim of this review is to specifically describe the mechanisms through which Roux-en-Y gastric bypass (RYGB) surgery enables weight loss for obese patients using observations from both human and animal studies. Perhaps most but not all clinicians would agree that the beneficial effects outweigh the harm of RYGB; however, the mechanisms for both the beneficial and deleterious (for example postprandial hypoglycaemia, vitamin deficiency and bone loss) effects are ill understood. The exaggerated release of the satiety gut hormones, such as GLP-1 and PYY, with their central and peripheral effects on food intake has given new insight into the physiological changes that happen after surgery. The initial enthusiasm after the discovery of the role of the gut hormones following RYGB may need to be tempered as the magnitude of the effects of these hormonal responses on weight loss may have been overestimated. The physiological changes after RYGB are unlikely to be due to a single hormone, or single mechanism, but most likely involve complex gut-brain signalling. Understanding the mechanisms involved with the beneficial and deleterious effects of RYGB will speed up the development of effective, cheaper and safer surgical and non-surgical treatments for obesity.
... Clinical studies on human patients demonstrate that the increase in oxalate excretion from baseline, 3 months after Roux-en-Y surgery, is moderate and below the level indicative of an increased risk for the development of kidney stones (< 45 mg/d) (35). ...
... Even more serious is oxalate nephropathy and potentially its end-stage, i.e. chronic renal failure. This complication is less frequent than nephrolithiasis, but by no means absolutely rare [43,[52][53][54][55][56][57]. ...
Bariatric surgery is increasingly performed on overweight individuals. A significant benefit with respect to cardiovascular
(CV) events and survival has been documented. After weight loss, reduction of albuminuria/proteinuria is almost consistently
seen; small studies documented retardation of the glomerular filtration rate (GFR) loss after bariatric surgery; reduction
of blood pressure (BP) is less consistent. It has been known for a long time that the frequency of oxalate stones is increased
after bariatric surgery. The main renal threat of hyperoxaluria is renal oxalosis, often irreversible, causing persisting
renal failure. The causes are reduced oxalate binding by calcium due to saponification of calcium causing fat malabsorption,
increased permeability for oxalate because of increased permeability of colon mucosa triggered by increased bile salts and
reduced colonization of the colon by oxalobacter formigenes. These mechanisms are susceptible to treatment.
... Others have made similar observations in other patient cohorts. [6][7][8] The risk of hyperoxaluria and perhaps kidney stones may be less with other forms of bariatric surgery [9][10][11] . However, the risk of kidney stones and/or CKD with bariatric surgery remains unclear, because these studies were either not population-based or lacked controls with similar obesity and comorbidities that did not undergo bariatric surgery. ...
Obesity, a risk factor for kidney stones and chronic kidney disease (CKD), is effectively treated with bariatric surgery. However, it is unclear whether surgery alters stone or CKD risk. To determine this we studied 762 Olmsted County, Minnesota residents who underwent bariatric surgery and matched them with equally obese control individuals who did not undergo surgery. The majority of bariatric patients underwent standard Roux-en-Y gastric bypass (RYGB; 78%), with the remainder having more malabsorptive procedures (very long limb RYGB or biliopancreatic diversion/duodenal switch; 14%) or restrictive procedures (laparoscopic banding or sleeve gastrectomy; 7%). The mean age was 45 years with 80% being female. The mean preoperative body mass index (BMI) was 46.7 kg/m(2) for both cohorts. Rates of kidney stones were similar between surgery patients and controls at baseline, but new stone formation significantly increased in surgery patients (11.0%) compared with controls (4.3%) during 6.0 years of follow-up. After malabsorptive and standard surgery, the comorbidity-adjusted hazard ratio of incident stones was significantly increased to 4.15 and 2.13, respectively, but was not significantly changed for restrictive surgery. The risk of CKD significantly increased after the malabsorptive procedures (adjusted hazard ratio of 1.96). Thus, while RYGB and malabsorptive procedures are more effective for weight loss, both are associated with increased risk of stones, while malabsorptive procedures also increase CKD risk.Kidney International advance online publication, 29 October 2014; doi:10.1038/ki.2014.352.
... Forms of malabsorptive bariatric surgery including Roux-en-Y gastric bypass and jejunoileal bypass are associated with enteric hyperoxaluria 19 , but not restrictive procedures such as gastric banding 20 . Rates of hyperoxaluria following malabsorptive gastric bypass procedures are estimated to be 20-29% 21,22 . The hyperoxaluria can be severe and can result in kidney failure. ...
Oxalate arthropathy is a rare cause of arthritis characterized by deposition of calcium oxalate crystals within synovial fluid. This condition typically occurs in patients with underlying primary or secondary hyperoxaluria. Primary hyperoxaluria constitutes a group of genetic disorders resulting in endogenous overproduction of oxalate, whereas secondary hyperoxaluria results from gastrointestinal disorders associated with fat malabsorption and increased absorption of dietary oxalate. In both conditions, oxalate crystals can deposit in the kidney leading to renal failure. Since oxalate is primarily renally eliminated, it accumulates throughout the body in renal failure, a state termed oxalosis. Affected organs can include bones, joints, heart, eyes, and skin. Since patients can present with renal failure and oxalosis before the underlying diagnosis of hyperoxaluria has been made, it is important to consider hyperoxaluria in patients who present with unexplained soft tissue crystal deposition. The best treatment of oxalosis is prevention. If patients present with advanced disease, treatment of oxalate arthritis consists of symptom management and control of the underlying disease process.
Obesity is the largest pandemic in the world, and its prevalence continues to increase. The purpose of the presented publication is to raise awareness of doctors about modern methods of diagnosing obesity and approaches to therapy, using an interdisciplinary team approach similar to that used in other chronic diseases, such as diabetes, heart disease and cancer. The article presents data from the World Gastroenterological Organization (2023) and the European Guidelines for the Treatment of Obesity in patients with diseases of the gastrointestinal tract and liver (2022). According to modern approaches, obesity should be considered as a chronic recurrent progressive disease, the treatment of which requires a comprehensive interdisciplinary approach involving psychologists and psychiatrists, nutritionists/nutritionists, therapists, endoscopists and surgeons, including lifestyle changes, a well-defined diet and exercise regimen, drug therapy, endoscopic or surgical methods of treatment. Conclusions. In order to stop the growing wave of obesity and its many complications and costs, doctors, insurance companies and health authorities should make systematic efforts to raise public awareness of both the adverse health risks associated with obesity and the potential reduction of risks through a comprehensive approach to therapy.
The development of kidney stones can be observed more frequently after bariatric and metabolic surgery than in the normal population. The trigger is a secondary hyperoxaluria, which occurs at a frequency of up to 29% in the first and even more often in the second postoperative year. Possible causes include both insufficient calcium and increased vitamin C supplementation.
Die Entwicklung von Nierensteinen kann nach einem adipositaschirurgischen Eingriff häufiger beobachtet werden im Vergleich zur Normalbevölkerung. Auslösend hierfür ist eine sekundäre Hyperoxalurie, die in einer Häufigkeit bis zu 29 % im ersten postoperativen Jahr und noch häufiger ab zwei Jahren nach der Operation auftritt. Als Ursache kommen unter anderem sowohl eine ungenügende Calcium-, als auch eine gesteigerte Vitamin C-Supplementation in Betracht.
Obesity is a global epidemic for which dietary and lifestyle modifications alone are ineffective treatment strategies. Subsequently, more patients are opting for bariatric surgery, which has better success rates in weight loss and improvement of obesity-related comorbidities. These procedures involve anatomic alterations of the gastrointestinal tract resulting in either restriction of intake or malabsorption of nutrients. While obesity itself is an independent risk factor for urolithiasis, bariatric surgery may also adversely affect stone risk. Restrictive procedures appear to have the lowest risk, whereas malabsorptive procedures are associated with the highest risks of stone formation. Stone prevention strategies including dietary manipulation are critical in the management of the patients who have had bariatric surgery.
Introduction:
Nephrolithiasis is common after malabsorptive bariatric surgery; however, the comparative risk of stone formation after different bariatric surgeries remains unclear. We seek to compare the risk of stone diagnosis and stone procedure after gastric banding (GB), sleeve gastrectomy (SG), short-limb Roux-en-Y (SLRY), long-limb Roux-en-Y (LLRY), and biliopancreatic diversion with duodenal switch (BPDDS).
Patients and Methods:
Using an administrative database, we retrospectively identified 116,304 patients in the United States, who received bariatric surgery between 2007 and 2014, did not have a known kidney stone diagnosis before surgery, and were enrolled in the database for at least 1 year before and after their bariatric surgery. We used diagnosis and procedural codes to identify comorbidities and events of interest. Our primary analysis was performed with extended Cox proportional hazards models using time to stone diagnosis and time to stone procedure as outcomes.
Results:
The adjusted hazard ratio of new stone diagnosis from 1 to 36 months, compared to GB, was 4.54 for BPDDS (95% confidence interval [CI] 3.66-5.62), 2.12 for LLRY (95% CI 1.74-2.58), 2.15 for SLRY (95% CI 2.02-2.29), and 1.35 for SG (95% CI 1.25-1.46). Similar results were observed for risk of stone diagnosis from 36 to 60 months, and for risk of stone removal procedure. Male sex was associated with an overall 1.63-fold increased risk of new stone diagnosis (95% CI 1.55-1.72).
Conclusions:
BPDDS was associated with a greater risk of stone diagnosis and stone procedures than SLRY and LLRY, which were associated with a greater risk than restrictive procedures. Nephrolithiasis is more common after more malabsorptive bariatric surgeries, with a much greater risk observed after BPDDS and for male patients.
Introduction:
Laparoscopic Roux-en-Y gastric bypass (LRYGB) is known to increase risk for calcium oxalate nephrolithiasis due to hyperoxaluria; however, nephrolithiasis rates after laparoscopic sleeve gastrectomy (LSG) are not well described. Our objective was to determine the rate of nephrolithiasis after LRYGB versus LSG.
Methods:
The electronic medical records of patients who underwent LRYGB or LSG between 2001 and 2017 were retrospectively reviewed.
Results:
1,802 patients were included. Postoperative nephrolithiasis was observed in 133 (7.4%) patients, overall, and 8.12% of LRYGB (122/1503) vs. 3.68% of LSG (11/299) patients (P < 0.001). Mean time to stone formation was 2.97 ± 2.96 years. Patients with a history of UTI (OR = 2.12, 95%CI 1.41-3.18; P < 0.001) or nephrolithiasis (OR = 8.81, 95%CI 4.93-15.72; P < 0.001) were more likely to have postoperative nephrolithiasis.
Conclusion:
The overall incidence of symptomatic nephrolithiasis after bariatric surgery was 7.4%. Patients who underwent LRYGB had a higher incidence of nephrolithiasis versus LSG. Patients with a history of stones had the highest risk of postoperative nephrolithiasis.
Metabolic surgery has emerged as the preferred sustainable treatment for the disease of obesity and its formidable health comorbidities. This evolution has resulted from major advances in surgical quality care including minimally invasive techniques and the introduction of accredited multidisciplinary centers of excellence. Multidisciplinary care including obesity medicine specialists, certified bariatric nurses, dietitians, and behavioral medicine professionals has improved perioperative care and helped to identify many early and late metabolic as well as nutritional complications of these procedures.
Purpose of review:
In this article, we aim to review the data regarding associations between obesity and nephrolithiasis to assist with workup and treatment of these intersecting disorders. As obesity has a multifactorial influence on the risk for urinary stone disease, the complicated mechanisms will be discussed to improve diagnosis and management.
Recent findings:
Obesity and metabolic syndrome interact with nephrolithiasis risk factors to produce a myriad of bodily responses that induce stone formation. For this reason, many societies recommend prompt metabolic workup to evaluate the precise causes of stone formation. Data have shown that dietary and directed medical therapies can produce an excellent therapeutic response in this patient population, although the response may be blunted compared with nonobese patients.
Summary:
Given the increasing number of obese and overweight patients, the urologist should be familiar with the pathophysiology, workup, and treatment of metabolic stone disease in this population, which are outlined here.
Obesity alone is a known risk factor for nephrolithiasis, and bariatric surgery has been linked to a higher incidence of post-operative new-onset nephrolithiasis. The mean interval from bariatric surgery to diagnosis of nephrolithiasis, ranges from 1.5 to 3.6 years.
The stone risk is greatest for purely malabsorptive procedures, intermediate for Roux-en-Y gastric bypass and lowest for purely restrictive procedures (laparoscopic adjustable gastric banding, laparoscopic sleeve gastrectomy) where it approaches or is reduced below that of non-operative obese controls. A history of nephrolithiasis and increasing age at the time of surgery are both associated with an increased risk of new stone formation post-operatively.
The underlying pathophysiologic changes following bariatric surgery include increased colonic absorption of oxalate leading to hyperoxaluria, hypocitraturia and increased urinary calcium oxalate supersaturation, which predispose to stone formation. The majority of incident stones are medically managed, with some requiring interventions in the form of lithotripsy or ureteroscopy.
Biliopancreatic diversion (BPD) surgery is one of the most efficacious bariatric procedures employed to manage morbid obesity. However, apart from a stable reduction of the body weight and beneficial action on the clinical course of various diseases associated with obesity, this method creates the risk of inducing osteometabolic disorders following the surgical intervention. We present here a clinical case of osteomalacia that developed in the late post-BPD period in the absence of regular intake of medicines and adequate medical care.
Oxalate Nephropathy is characterised by the presence of tubular crystalline deposits of calcium oxalate, which can lead to both acute and chronic tubular injury and progressive renal failure. Enteric hyperoxaluria is the most common cause of moderate hyperoxaluria; it occurs in conditions associated witah fat or bile acid malabsorption, which include jejunoileal bypass and other bariatric procedures such as Roux ‑en ‑Y gastric bypass surgery. We present the clinical case of a 69 ‑year ‑old man who was hospitalised for non ‑oliguric renal dysfunction, with a serum creatinine of 10 mg/dl and normocytic normochromic anaemia. There was no prior history of renal disease. Twenty months before admission the patient was diagnosed with a gastro ‑oesophageal junction adeno‑ carcinoma and was treated with pre ‑operative chemotherapy, followed by total gastrectomy, with a Roux ‑en ‑Y gastric bypass reconstruction. On discharge from gastric surgery, renal function was normal. On the first day of hospital stay haemodialysis was initiated. Over the following days, the rapid unexplained renal impairment was investigated, and this workup [2] included a kidney biopsy. Histological examination of the biopsy specimen revealed a predominantly interstitial nephropathy with tubular atrophy and interstitial fibrosis, with bright intra ‑tubular calcium oxalate crystals in over 50% of the tubules and so the histological diagnosis was of oxalate nephropathy. Subsequently, no recovery of renal function was observed, so the patient is currently undergoing regular haemodialysis. Oxalate nephropathy is a rare but severe complication of Roux ‑en ‑Y gastric bypass surgery that can lead to a rapid progression to kidney failure. Although the treatment of obesity is the main indication for this surgery, this is also the preferred approach for gastrointestinal reconstruction after total gastrectomy for treatment of gastric carcinoma. Considering the rapid progression of oxalate nephropathy to kidney failure, patients who undergo Roux ‑en ‑Y gastric bypass surgery should have regular follow ‑up of renal function.
Obesity is an overwhelming epidemic with implications for all aspects of medicine. Urology is no exception, and specifically obesity has had a pronounced effect on stone disease. Obese patients are at a greatly increased risk for all stones, but particularly uric acid stones. The understanding of the physiology of urolithiasis in obese patients will improve both the prevention and medical treatment of stones. Currently, surgery is the definite treatment, but obstacles exist that complicate surgery in obese persons. A review of the literature, experience of urologists, and current recommendations for accommodations for obese patients are described here within.
Obesity (body mass index (BMI) above 30 kg/m2) has become an epidemic condition that affects 10-27% of men and up to 38% of women in European countries. In the United States, more than 5% of the adult population are considered morbidly obese (BMI of 40 kg/m2 or more). Worldwide, more than 300 million people are estimated to be obese. According to recent epidemiologic studies, greater BMI, greater weight, larger waist circumference, and heavy weight gain are independently associated with increased risk for renal stone formation. This appears to be related to two distinct metabolic conditions: (1) Abdominal obesity in the context of the so-called metabolic syndrome predisposes to insulin resistance, which at the renal level appears to cause reduced urinary ammonium excretion and low urine pH. The consequence is an increased risk for uric acid stone formation. (2) Bariatric surgery, more and more popular as the only intervention that facilitates significant weight loss in morbidly obese people, has been shown to increase the risk for calcium oxalate nephrolithiasis. The underlying pathophysiologic mechanisms may be enteric hyperoxaluria due to fat malabsorption or decreased intestinal colonization with oxalate-degrading bacteria.
Kidney stones cause significant morbidity worldwide. Most stones passed by patients in the US are calcium based. After the initial episode, a metabolic evaluation to search for the underlying causes is recommended. Kidney stones may lead to CKD. The incidence of recurrent stone formation decreases with progressive CKD, however, leading to under-recognition of the relationship. In general, to prevent recurrence of calcium-based stones, dietary modifications to increase fluid intake, reduce salt and animal protein intake, and encourage consumption of an age- and gender-appropriate amount of calcium, preferably from dairy sources and not supplements, is recommended. Restriction of foods rich in oxalate is also important to reduce recurrence rates. Determination of urinary supersaturation and analysis of any passed stones guide treatment. Measures to reduce urinary supersaturation are highly effective in lowering recurrent stone formation. Targeted medical therapy can be initiated once a metabolic abnormality is found. Medications used to prevent stone recurrence are well tolerated and highly effective. Thiazide diuretics are a cornerstone of therapy in patients who form calcium-containing kidney stones. Potassium citrate is also highly effective in reducing recurrent stone formation.
Obesity is a significant health concern and is associated with an increased risk of nephrolithiasis, particularly in women. The underlying pathophysiology of stone formation in obese patients is thought to be related to insulin resistance, dietary factors, and a lithogenic urinary profile. Uric acid stones and calcium oxalate stones are common in these patients. Use of surgical procedures for obesity (bariatric surgery) has risen over the past two decades. Although such procedures effectively manage obesity-dependent comorbidities, several large, controlled studies have revealed that modern bariatric surgeries increase the risk of nephrolithiasis by approximately twofold. In patients who have undergone bariatric surgery, fat malabsorption leads to hyperabsorption of oxalate, which is exacerbated by an increased permeability of the gut to oxalate. Patients who have undergone bariatric surgery show characteristic 24 h urine parameters including low urine volume, low urinary pH, hypocitraturia, hyperoxaluria and hyperuricosuria. Prevention of stones with dietary limitation of oxalate and sodium and a high intake of fluids is critical, and calcium supplementation with calcium citrate is typically required. Potassium citrate is valuable for treating the common metabolic derangements as it raises urinary pH, enhances the activity of stone inhibitors, reduces the supersaturation of calcium oxalate, and corrects hypokalaemia. Both pyridoxine and probiotics have been shown in small studies to reduce hyperoxaluria, but further study is necessary to clarify their effects on stone morbidity in the bariatric surgery population.
Significant advances have taken place in medicine over the past century. In addition, increasing rates of obesity, diabetes mellitus, and metabolic syndrome have resulted in increasing rates of stones among men and women. Within 1 year of forming a calcium oxalate stone, 10 % of men will form another calcium oxalate stone, and 50 % will form another stone within 10 years.
Males are affected three times as frequently as females for stones. Testosterone clearly has an impact on this; however, the rates of nephrolithiasis among women are increasing. Urine studies have demonstrated a decrease in urinary pH (>5.5) and an increase in uric acid supersaturation. This has resulted in increased rates of uric acid stones. In addition, obesity surgery has increased the risk of calcium oxalate stone formation.
All of these factors combined have had a profound influence on the patterns of stone disease. Lifestyles have significantly affected the prevalence of kidney stone disease. In this chapter, we will review the impact of societal changes on stone patterns.
Urine oxalate measurement is an important investigation in the evaluation of renal stone disease. Primary hyperoxaluria (PH) is a rare inherited metabolic disease characterised by persistently elevated urine oxalate, but the diagnosis may be missed in adults until renal failure has developed. Urine oxalate results were reviewed to compare oxalate:creatinine ratio and oxalate excretion, and to estimate the potential numbers of undiagnosed PH.
Urine oxalate results from August 2011 to April 2013 were reviewed. Oxalate excretion and oxalate:creatinine ratio were evaluated for 24 h collections and ratio alone for spot urine samples.
Oxalate:creatinine ratio and oxalate excretion were moderately correlated (R = 0.63) in 24-h urine collections from patients aged 18 years and above. Sex-related differences were found requiring implementation of male and female reference ranges for oxalate:creatinine ratio. Of samples with both ratio and excretion above the reference range, 7% came from patients with confirmed PH. There were 24 patients with grossly elevated urine oxalate who had not been evaluated for PH.
Oxalate:creatinine ratio and oxalate excretion were discordant in many patients, which is likely to be a result of intra-individual variation in creatinine output and imprecision in the collection itself. Some PH patients had urine oxalate within the reference range on occasion, and therefore it is not possible to exclude PH on the finding of a single normal result. A significant number of individuals had urine oxalate results well above the reference range who potentially have undiagnosed PH and are consequently at risk of renal failure.
With the increasing epidemic of obesity in the United States as well as abroad, bariatric surgery has emerged as the most effective and sustained treatment for reduction. This treatment modality has been well recognized to diminish the risk of cardiovascular morbidity and mortality and ameliorate diabetes mellitus. However, with time, derangement in mineral metabolism has emerged as a major complication in this population. Population-based study has shown increased prevalence of bone fractures and kidney stone formation following bariatric surgery. The risk appears to be more specific after Roux-en-Y gastric bypass procedures, the most common surgical approach among this population. Over the past decade, there have been advances in the understanding of pathophysiologic mechanisms of both bone loss and kidney stone disease in these patients. The understanding of these underlying pathophysiologic mechanisms may lead to the development of drug therapies that ameliorate this complication. Unfortunately, at the present time, there is no hard data on any specific treatment showing decreased incidence of fragility fractures or kidney stone passage. However, some studies suggest that calcium and vitamin D supplementation may decrease bone loss and bone turnover, and as a result, increase bone mineral density in this population. However, there is concern with the development of kidney stone formation following such an approach. A novel treatment approach would be the use of effervescent potassium calcium citrate that not only prevents complications of bone loss but may diminish the risk of kidney stone formation. Despite preliminary results showing the effectiveness of this drug in the reduction in the parathyroid hormone, bone turnover, and improvement in the urinary saturation marker showing effectiveness against calcium oxalate and uric acid stones, there is no hard data available to support the effectiveness of this treatment in the reduction in fragility fractures or kidney stone incidence. Such studies to explore this effect must be considered in the future.
Bariatric surgery is now recognized as a sure and effective way for weight reduction in morbid obesity. However some procedures induce intestinal malabsorption leading to enteric hyperoxaluria. So bariatric surgery could place these patients not only at risk for nephrolithiasis but also for oxalate induced nephropathy and chronic renal failure. Because of the growing incidence of obesity worldwide, physicians and patients should be aware of such potential complications. There is no mean to discuss this treatment because of its spectacular efficiency on obesity and its comorbidities. But it is necessary to choose the surgical technique according to the risk factors of the patients. Following surgery, preventive treatment strategies are indicated, such as modified dietary lifestyle and specific drugs as we suggested to limit or even avoid these complications. However observance could fail in the long term. In case of oxalate nephropathy, surgery may be proposed to restore the intestinal tract but with the risk of overweight relapse. To illustrate this matter, we report here significant observations of three patients, which, having successfully benefited from the same bariatric surgery, have presented lithiasic complications for two of them and oxalate nephropathy leading to chronic renal failure and hemodialysis for the third.
Historically, the development of enteric hyperoxaluria has been well recognized as a potential risk following the bariatric procedures jejunoileal bypass (JIB) and distal bypass. However, the occurrence of enteric hyperoxaluria has not been recognized as an associated, prevalent risk after Roux-en-Y gastric bypass (RYGBP). An increased rate of nephrolithiasis was observed in the Roux-en-Y patient population at the Columbia University Center for Metabolic & Weight Loss Surgery. A representative case of recurrent bilateral oxalate stone formation in a patient following RYGBP at the center is reported. Enteric hyperoxaluria and nephrolithiasis must be considered potential risks associated with any malabsorptive surgery, including RYGBP. Prevention of the development of hyperoxaluria is multifactorial and includes recognition of potential preoperative risk factors, postoperative follow-up evaluations, and attentive nutritional guidance. These patient management areas represent opportunities that need to be recognized and addressed in the prevention of hyperoxaluria in patients undergoing RYGBP.
Background:
The objective of this study was to assess predictors for new-onset stone formers after Roux-en-Y gastric bypass (RYGBP).
Methods:
One hundred and fifty-one obese patients underwent RYGBP and were followed for 1 year. The analysis comprised two study time points: preoperative (T0) and 1 year after surgery (T1). They were analyzed for urinary stones, blood tests, and 24-h urinary evaluation. Nonparametric tests, logistic regression, and multivariate analysis were conducted using SPSS 17.
Results:
Median BMI decreased from 44.1 to 27.0 kg/m2 (p < 0.001) in the postoperative period. Urinary oxalate (24 versus 41 mg; p < 0.001) and urinary uric acid (545 versus 645 mg; p < 0.001) increased significantly postoperatively (preoperative versus postoperative, respectively). Urinary volume (1310 versus 930 ml; p < 0.001), pH (6.3 versus 6.2; p = 0.019), citrate (268 versus 170 mg; p < 0.001), calcium (195 versus 105 mg; p < 0.001), and magnesium (130 versus 95 mg; p = 0.004) decreased significantly postoperatively (preoperative versus postoperative, respectively). Stone formers increased from 16 (10.6 %) to 27 (17.8%) patients in the postoperative analysis (p = 0.001). Predictors for new stone formers after RYGBP were postoperative urinary oxalate (p = 0.015) and uric acid (p = 0.044).
Conclusions:
RYGBP determined profound changes in urinary composition which predisposed to a lithogenic profile. The prevalence of urinary lithiasis increased almost 70% in the postoperative period. Postoperative urinary oxalate and uric acid were the only predictors for new stone formers.
Enteric hyperoxalosis is a recognized complication of bariatric surgery, with consequent oxalate nephropathy leading to chronic kidney disease and occasionally end-stage renal failure. In patients with prior gastrointestinal bypass surgery, renal allografts are also at risk of oxalate nephropathy. Further, transplant recipients may be exposed to additional causes of hyperoxalosis. We report two cases of renal allograft oxalate nephropathy in patients with remote histories of bariatric surgery. Conservative management led to improvement of graft function in one patient, while the other patient returned to dialysis. Interpretation of serologic, urine and biopsy studies is complicated by oxalate accumulation in chronic renal failure, and heightened excretion in the early posttransplant period. A high index of suspicion and careful clinicopathologic correlation on the part of transplant nephrologists and renal pathologists are required to recognize and treat allograft oxalate nephropathy. As the incidence of obesity and pretransplant bariatric surgery increases in the transplant population, allograft oxalate nephropathy is likely to be an increasing cause of allograft dysfunction.
Anaerobic bacteria that metabolize oxalic acid have only recently been isolated from the rumen and from other gastrointestinal habitats. They constitute a new genus and species, Oxalobacter formigenes. This report presents the first comparison of cultural counts of these organisms from human feces and indicates that numbers as high as 10(7)/g may be present in feces from normal humans. Rates of oxalate degradation by mixed bacterial populations in feces from seven normal humans ranged from 0.1 to 4.8 mumol/(g X h). With fecal samples from eight patients that had undergone jejunoileal bypass surgery, rates were much lower [0-0.006 mumol/(g X h)]. We propose that oxalic acid degradation by Oxalobacter formigenes may influence absorption of oxalate from the intestine and that lower rates or lack of oxalate degradation in the colons of jejunoileal bypass patients may contribute to the increased absorption of dietary oxalate and the hyperoxaluria commonly associated with such patients.
This report describes a new group of anaerobic bacteria that degrade oxalic acid. The new genus and species, Oxalobacter formigenes, are inhabitants of the rumen and also of the large bowel of man and other animals where their actions in destruction of oxalic acid may be of considerable importance to the host. Isolates from the rumen of a sheep, the cecum of a pig, and from human feces were all similar Gram-negative, obligately anaerobic rods, but differences between isolates in cellular fatty acid composition and in serologic reaction were noted. Measurements made with type strain OxB indicated that 1 mol of protons was consumed per mol of oxalate degraded to produce approximately 1 mol of CO2 and 0.9 mol of formate. Substances that replaced oxalate as a growth substrate were not found.
The action of various beverages and foods on the composition of the urine in the circadian rhythm and in the 24-hour urine has been investigated under standardized conditions. Orange juice leads to a significant increase of urinary pH and citric acid excretion. Black tea leads to a raised excretion of oxalic acid by only 7.9%. In the short term, beer increases diuresis, but afterwards leads to a compensatory antidiuresis with increased risk of stone formation. Depending on their composition, mineral waters have very different effects on the urinary constituents. Milk as well as cocoa beverage significantly increase calcium excretion; moreover, cocoa causes an increase in the oxalic acid excretion. The leafy vegetable foods containing oxalate, e.g., spinach and rhubarb, lead to peaks of oxalate excretion of 300-400% in the circadian excretion curve. Cheese leads to a significant rise of calcium excretion with acidification of the urine and lowering of citrate excretion. Calcium excretion is increased by 30% by sodium chloride. Foods containing purine result in an increased uric acid excretion over several days. Depending on their phytic acid content, brans bind calcium, but lead to an increased oxalic acid excretion. Analysis of the urine indicates that average diet in Germany entails a high risk of urinary stone formation. As a result of the change to a balanced mixed or vegetarian diet, according to the requirements, significant alterations in urinary pH, calcium, magnesium, uric acid, citric acid, cystine, and glycosaminoglycan excretion are measured, resulting in a drastic reduction in the risk of urinary stone formation.
Overweight and obesity are increasing dramatically in the United States and most likely contribute substantially to the burden of chronic health conditions.
To describe the relationship between weight status and prevalence of health conditions by severity of overweight and obesity in the US population.
Nationally representative cross-sectional survey using data from the Third National Health and Nutrition Examination Survey (NHANES III), which was conducted in 2 phases from 1988 to 1994.
A total of 16884 adults, 25 years and older, classified as overweight and obese (body mass index [BMI] > or =25 kg/m2) based on National Institutes of Health recommended guidelines.
Prevalence of type 2 diabetes mellitus, gallbladder disease, coronary heart disease, high blood cholesterol level, high blood pressure, or osteoarthritis.
Sixty-three percent of men and 55% of women had a body mass index of 25 kg/m2 or greater. A graded increase in the prevalence ratio (PR) was observed with increasing severity of overweight and obesity for all of the health outcomes except for coronary heart disease in men and high blood cholesterol level in both men and women. With normal-weight individuals as the reference, for individuals with BMIs of at least 40 kg/m2 and who were younger than 55 years, PRs were highest for type 2 diabetes for men (PR, 18.1; 95% confidence interval [CI], 6.7-46.8) and women (PR, 12.9; 95% CI, 5.7-28.1) and gallbladder disease for men (PR, 21.1; 95% CI, 4.1-84.2) and women (PR, 5.2; 95% CI, 2.9-8.9). Prevalence ratios generally were greater in younger than in older adults. The prevalence of having 2 or more health conditions increased with weight status category across all racial and ethnic subgroups.
Based on these results, more than half of all US adults are considered overweight or obese. The prevalence of obesity-related comorbidities emphasizes the need for concerted efforts to prevent and treat obesity rather than just its associated comorbidities.
Public health officials and organizations have disseminated health messages regarding the dangers of obesity, but these have not produced the desired effect.
To estimate the expected number of years of life lost (YLL) due to overweight and obesity across the life span of an adult.
Data from the (1) US Life Tables (1999); (2) Third National Health and Nutrition Examination Survey (NHANES III; 1988-1994); and (3) First National Health and Nutrition Epidemiologic Follow-up Study (NHANES I and II; 1971-1992) and NHANES II Mortality Study (1976-1992) were used to derive YLL estimates for adults aged 18 to 85 years. Body mass index (BMI) integer-defined categories were used (ie, <17; 17 to <18; 18 to <19; 20 to <21; 21 to 45; or > or =45). A BMI of 24 was used as the reference category.
The difference between the number of years of life expected if an individual were obese vs not obese, which was designated YLL.
Marked race and sex differences were observed in estimated YLL. Among whites, a J- or U-shaped association was found between overweight or obesity and YLL. The optimal BMI (associated with the least YLL or greatest longevity) is approximately 23 to 25 for whites and 23 to 30 for blacks. For any given degree of overweight, younger adults generally had greater YLL than did older adults. The maximum YLL for white men aged 20 to 30 years with a severe level of obesity (BMI >45) is 13 and is 8 for white women. For men, this could represent a 22% reduction in expected remaining life span. Among black men and black women older than 60 years, overweight and moderate obesity were generally not associated with an increased YLL and only severe obesity resulted in YLL. However, blacks at younger ages with severe levels of obesity had a maximum YLL of 20 for men and 5 for women.
Obesity appears to lessen life expectancy markedly, especially among younger adults.
The increasing prevalence and associated sociodemographic disparities of morbid obesity are serious public health concerns. Bariatric surgical procedures provide greater and more durable weight reduction than behavioral and pharmacological interventions for morbid obesity.
To examine trends for elective bariatric surgical procedures, patient characteristics, and in-hospital complications from 1998 to 2003 in the United States.
The Nationwide Inpatient Sample was used to identify bariatric surgery admissions from 1998-2002 (with preliminary data for 12 states from 2003) using International Classification of Diseases, Ninth Revision, codes for foregut surgery with a confirmatory diagnosis of obesity or by diagnosis related group code for obesity surgery. Annual estimates and trends were determined for procedures, patient characteristics, and adjusted complication rates.
Trends in bariatric surgical procedures, patient characteristics, and complications.
The estimated number of bariatric surgical procedures increased from 13,365 in 1998 to 72,177 in 2002 (P<.001). Based on preliminary state-level data (1998-2003), the number of bariatric surgical procedures is projected to be 102 794 in 2003. Gastric bypass procedures accounted for more than 80% of all bariatric surgical procedures. From 1998 to 2002, there were upward trends in the proportion of females (81% to 84%; P = .003), privately insured patients (75% to 83%; P = .001), patients from ZIP code areas with highest annual household income (32% to 60%, P<.001), and patients aged 50 to 64 years (15% to 24%; P<.001). Length of stay decreased from 4.5 days in 1998 to 3.3 days in 2002 (P<.001). The adjusted in-hospital mortality rate ranged from 0.1% to 0.2%. The rates of unexpected reoperations for surgical complications ranged from 6% to 9% and pulmonary complications ranged from 4% to 7%. Rates of other in-hospital complications were low.
These findings suggest that use of bariatric surgical procedures increased substantially from 1998 to 2003, while rates of in-hospital complications were stable and length of stay decreased. However, disparities in the use of these procedures, with disproportionate and increasing use among women, those with private insurance, and those in wealthier ZIP code areas should be explored further.
This paper describes national trends in gastric bypass procedures from 1998 through 2003 and explores the demographic and health profile of those who receive this procedure. Short-term outcomes such as length of stay and in-hospital complication rates are also examined.
Data on obese hospital inpatients who had gastric bypass were obtained from the 1998 to 2003 National Hospital Discharge Survey. Gastric bypass was reported for an estimated 288,000 discharges during the 6-year study period. Trends within the 6-year period were tested using weighted regression. Characteristics of gastric bypass patients were compared with those of other inpatients using a chi(2) test of independence and the two-sided t test.
The estimated number of hospital discharges with gastric bypass increased significantly, from 14,000 in 1998 to 108,000 in 2003. During this period, the average length of stay declined by 56% from 7.2 to 3.2 days. Gastric bypass patients were primarily women (84%), 25 to 54 years of age (82%), and privately insured (76%). A 1 in 10 complication rate was found for discharges with gastric bypass.
Gastric bypass procedures in the United States have increased rapidly since 1998, whereas the average hospital stay has decreased. The decreasing length of stay needs to be evaluated in conjunction with potential complication rates and the permanent change in anatomy and lifestyle that must accompany this procedure. Monitoring trends in use of this procedure is important, especially if reimbursement policies change and the epidemic of obesity continues.
The primary goal of this study was to test the hypothesis that Oxalobacter colonization alters colonic oxalate transport thereby reducing urinary oxalate excretion. In addition, we examined the effects of intraluminal calcium on Oxalobacter colonization and tested the hypothesis that endogenously derived colonic oxalate could be degraded by lyophilized Oxalobacter enzymes targeted to this segment of the alimentary tract. Oxalate fluxes were measured across short-circuited, in vitro preparations of proximal and distal colon removed from Sprague-Dawley rats and placed in Ussing chambers. For these studies, rats were colonized with Oxalobacter either artificially or naturally, and urinary oxalate, creatinine and calcium excretions were determined. Colonized rats placed on various dietary treatment regimens were used to evaluate the impact of calcium on Oxalobacter colonization and whether exogenous or endogenous oxalate influenced colonization. Hyperoxaluric rats with some degree of renal insufficiency were also used to determine the effects of administering encapsulated Oxalobacter lysate on colonic oxalate transport and urinary oxalate excretion. We conclude that in addition to its intraluminal oxalate-degrading capacity, Oxalobacter interacts physiologically with colonic mucosa by inducing enteric oxalate secretion/excretion leading to reduced urinary excretion. Whether Oxalobacter, or products of Oxalobacter, can therapeutically reduce urinary oxalate excretion and influence stone disease warrants further investigation in long-term studies in various patient populations.
The prevalence of overweight in children and adolescents and obesity in adults in the United States has increased over several decades.
To provide current estimates of the prevalence and trends of overweight in children and adolescents and obesity in adults.
Analysis of height and weight measurements from 3958 children and adolescents aged 2 to 19 years and 4431 adults aged 20 years or older obtained in 2003-2004 as part of the National Health and Nutrition Examination Survey (NHANES), a nationally representative sample of the US population. Data from the NHANES obtained in 1999-2000 and in 2001-2002 were compared with data from 2003-2004.
Estimates of the prevalence of overweight in children and adolescents and obesity in adults. Overweight among children and adolescents was defined as at or above the 95th percentile of the sex-specific body mass index (BMI) for age growth charts. Obesity among adults was defined as a BMI of 30 or higher; extreme obesity was defined as a BMI of 40 or higher.
In 2003-2004, 17.1% of US children and adolescents were overweight and 32.2% of adults were obese. Tests for trend were significant for male and female children and adolescents, indicating an increase in the prevalence of overweight in female children and adolescents from 13.8% in 1999-2000 to 16.0% in 2003-2004 and an increase in the prevalence of overweight in male children and adolescents from 14.0% to 18.2%. Among men, the prevalence of obesity increased significantly between 1999-2000 (27.5%) and 2003-2004 (31.1%). Among women, no significant increase in obesity was observed between 1999-2000 (33.4%) and 2003-2004 (33.2%). The prevalence of extreme obesity (body mass index > or =40) in 2003-2004 was 2.8% in men and 6.9% in women. In 2003-2004, significant differences in obesity prevalence remained by race/ethnicity and by age. Approximately 30% of non-Hispanic white adults were obese as were 45.0% of non-Hispanic black adults and 36.8% of Mexican Americans. Among adults aged 20 to 39 years, 28.5% were obese while 36.8% of adults aged 40 to 59 years and 31.0% of those aged 60 years or older were obese in 2003-2004.
The prevalence of overweight among children and adolescents and obesity among men increased significantly during the 6-year period from 1999 to 2004; among women, no overall increases in the prevalence of obesity were observed. These estimates were based on a 6-year period and suggest that the increases in body weight are continuing in men and in children and adolescents while they may be leveling off in women.
Hyperoxaluria was documented in patients with pancreatic insufficiency, adult celiac disease, regional enteritis after ileectomy and partial colectomy, and jejunoileal bypass. The degree of hyperoxaluria correlated directly with the severity of the steatorrhea and inversely with the dietary calcium content. High-calcium diets suppressed oxalate excretion to normal when fecal fat excretion was approximatelys 30 g/day or less. In patients with more severe steatorrhea, decreasing dietary fat and oxalate content further reduced urinary oxalate excretion. These data suggest that while steatorrhea is the most important determinant for enhanced absorption of dietary oxalate, variations in dietary calcium content modulate the amount of oxalate absorbed.
The concept that calcium stone formation may be explained on the basis of a number of risk factors is developed. The main risk factors involved are shown to be calcium, oxalate, pH, acid mucopolysaccharides and uric acid.
A method is described for calculating and combining the individual risk factors into a measure of the “relative probability” of forming stones (P SF ).
P SF values are generally lower in normal subjects than in stone‐formers. Amongst the normals, P SF values are lower in children and women than in men.
Recurrent stone‐formers have the highest P SF values and these correlate well with the severity of the disease as defined by the stone episode rate of the patient. Single stone‐formers have P SF values intermediate between those of normal men and those of recurrent stone‐formers.
Five hundred and seventeen patients who had a jejunoileal bypass performed at the University of Minnesota Hospitals were studied with regard to the formation of urinary calculi postoperatively. A 9 per cent incidence of stones was found in the 365 patients for whom complete data were available. Men were affected more commonly than women. Of particular note was the correlation between long term oral supplementation of calcium postoperatively and a delay in the onset of symptomatic urolithiasis. A group of 91 recent patients who have been maintained on orally administered calcium are stone-free as long as 12 months after operation, again suggesting that supplementation of calcium may help prevent urolithiasis in patients who have had a bypass procedure.
To investigate the role of the colon in increased oxalate absorption, we measured urinary oxalate and fecal fat excretion in 26 patients with gastrointestinal disease. Eight patients with steatorrhea of various causes (Crohn's disease [two], chronic pancreatitis [four], jejunoileal bypass [one] and extrahepatic biliary obstruction [one]) had hyperoxaluria (greater than 45 mg per 24 hours). All these patients had intact colons. In contrast, none of five patients with ileostomies and steatorrhea secondary to ileal resection had hyperoxaluria. Absorption of 14C-oxalate was increased in three patients with steatorrhea and intact colons but not in three patients with steatorrhea and an ileostomy. Thus, the colon is both the site of and required for increased oxalate absorption in enteric hyperoxaluria. The lack of a direct relation between fecal fat excretion and urinary oxalate excretion in the patients with hyperoxaluria and steatorrhea suggests that steatorrhea, although important, is not the only determinant in the pathogenesis of hyperoxaluria.
There have been 543 jejuno-ileal bypass patients screened for the presence of urinary calculi 1 to 6 years postoperatively. Of these patients 9 per cent have had 1 to 2 calculi during the followup and 3 per cent have had multiple calculi. Ninety-four per cent of the recovered calculi consisted entirely of calcium oxalate. Seven patients had a history of stones before the bypass, 6 of whom have had additional stones postoperatively. To define the conditions associated with stone formation in these patients measurements of serum and urinary oxalate concentration, urinary calcium oxalate saturation, urinary crystal size distribution, and the rates of intestinal oxalate absorption and urinary crystallization have been performed on patients who did and did not have stones postoperatively. On the basis of these studies it appears that the patients in whom stones formed differ from those in whom they did not form only in the rate of urinary crystallization and in the number of large crystal particles present in the urine. Evaluation of current therapeutic modalities in terms of the capability to correct these stone-forming characteristics and to reduce actual calculus formation reveals that the only successful regimen is that which includes an extreme reduction of oxalate ingestion.
Two hundred massively obese patients were submitted to four variations of jejunoileal bypass during the last decade. The operative mortality rate was 2.5 per cent. Nonfatal postoperative complications occurred in patients who had the small intestine shortened to 18 to 20 inches by end-to-end jejunoileostomy. In follow-up periods up to ten years, there have been nine late fatalities, five of which were unrelated to jejunoileal bypass. Despite late complications which have included renal stones, enterohepatic syndrome and ventral hernia, 66 per cent of the survivors have achieved good results by the criteria used. Metabolic improvements include a profound and sustained reduction in plasma concentrations of cholesterol and triglyceride.
Hyperoxaluria was documented in patients with pancreatic insufficiency, adult celiac disease, regional enteritis after ileectomy and partial colectomy, and jejunoileal bypass. The degree of hyperoxaluria correlated directly with the severity of the steatorrhea and inversely with the dietary calcium content. High-calcium diets suppressed oxalate excretion to normal when fecal fat excretion was approximately 30 g/day or less. In patients with more severe steatorrhea, decreasing dietary fat and oxalate content further reduced urinary oxalate excretion. These data suggest that, while steatorrhea is the most important determinant for enhanced absorption of dietary oxalate, variations in dietary calcium content modulate the amount of oxalate absorbed.
Since 1962, jejunoileal bypass has been performed on 59 male and 171 female subjects, aged 18 to 55 years; these patients were followed clinically. Postoperative weight loss at two years averaged 37% in men and 35% in women. Hypokalemia (23%), hypocalcemia (22%), hypoalbuminemia (9%), metabolic acidosis (14%), elevated liver enzyme values (41%), and hyperbilirubinemia (6%), were the most commonly encountered blood chemical alterations. Complications were arthritis syndrome (men, 8%; women, 19%). urinary calculi (men, 24%; women, 10%), cholelithiasis (men, 10%; women, 9%), liver impairment (men, 2%; women, 6%), and major emotional upset (men, 8%; women, 9%). Forty-nine percent of the men and 51% of the women required rehospitalization for management of complications, surgery for hernia, anorectal disorders, nutritional support, and metabolic study. There were 19 bypass-related deaths (8%), including 10 due to liver failure.
These studies were designed to evaluate the effect of bile salts and fatty acids on colonic oxalate absorption. Five millimolar deoxycholate significantly increased oxalate absorption from 34.2 +/- 9.4 nmoles per min per g dry weight to 330.4 +/- 47.3 (P less than 0.001) and changed water absorption to water secretion. Deoxycholate also increased the absorption of urea, decreased the electrical potential difference, and increased colonic clearance of oxalate, observations which are consistent with an increase in colonic mucosal permeability. In contrast, taurocholate did not increase oxalate absorption. Ricinoleic acid also significantly increased the absorption. These results suggest that bile salts and fatty acids increase colonic absorption of oxalate. Oleic acid had similar effects on oxalate absorption but was less effective than ricinoleic acid. Octanoic acid, a medium chain fatty acid, did not alter oxalate absorption of oxalate by a nonspecific alteration of mucosal permeability. These observations may further explain many of the clinical phenomena associated with enteric hyperoxaluria.
Since 1977, we have managed 56 patients (36 Payne and 20 Scott bypasses) with late (one to 18 years) complications resulting from a jejunoileal bypass. All patients underwent a one-stage conversion of the jejunoileal bypass to a gastric bypass. Patients were classified according to postbypass weight, the need for nutritional support, the type and severity of complication, and the time interval between jejunoileal bypass and the onset of the complication and correction of the complication. There were no operative deaths; one patient died 18 months after surgery of cirrhosis. The complication rate was 34%; however, most complications were minor. Our experience with this procedure has shown it to be highly effective in correcting complications other than polyarthritis. When coupled with nutritional support, it is safe even in malnourished patients.
Our opinion of the present state of jejunoileal shunt in the treatment of obesity may be summarized as follows: (1) A jejunoileal shunt is of distinct benefit in selected patients for whom the obese state has become a hazard to health. (2) It is not the procedure one does because an obese patient is 25 to 50 pounds overweight. (3) Inasmuch as a high degree of cooperation is essential, a relationship of mutual respect, trust, and responsibility must be present between the physician and patient. A hostile attitude on the part of the patient cannot be tolerated. (4) Although long-range benefits from the control of factors leading to aggravation of cardiovascular disorders may be expected, it may be dangerous to subject patients with well established cardiovascular disease to this procedure. (5) A jejunocolic shunt should not be used for control of obesity. (6) A jejunoileal shunt should definitely be considered as an investigative procedure, for the present, and should not be undertaken unless facilities are available to handle complications and to conduct significant research into the mechanism of obesity and its attendant complications over a long period of time.
Fifty-two patients undergoing jejunoileal bypass surgery were prospectively evaluated to determine: 1) the incidence of the associated arthritic syndrome; 2) whether we could identify patients at risk for arthritis prior to surgery; and 3) changes in immune function. The incidence of arthritis was 28% and was frequently associated with dermatitis. No preoperative clinical or laboratory parameters identified those patients at risk to develop rheumatic problems. Circulating immune complexes were found in both arthritis and non-arthritis patients after surgery. Mean serum levels of IgA rose significantly after surgery only in patients who developed arthritis, but remained within the normal range. No other immunologic abnormalities were noted.
To evaluate the results of jejunoileal bypass for morbid obesity, we studied 100 patients with intact bypasses an average of more than five years after surgery. Mean weight loss at five years was 102.7 lb (46.6 kg) (33 per cent). Although nearly half the patients regained some weight between one and five years after surgery, only 17 per cent regained 20 lb (9 kg) or more. Medical benefits (such as improved glucose tolerance and lowered blood pressure) were maintained at five years, but side effects and complications continued to occur in the late postoperative period. Diarrhea (more than three stools per day) persisted in 58 per cent of the patients, and electrolyte disturbances occurred in over a third. Diminished levels of B12 or folate or both were present in 88 per cent. Twenty-one per cent of the patients had nephrolithiasis, and 20 per cent of those who were at risk required cholecystectomy. Progressive hepatic structural abnormalities occurred in 29 per cent of the patients, and there was a 7 per cent incidence of cirrhosis. Although 81 per cent of the patients had satisfactory results at five years, side effects and complications continued to occur, mandating careful follow-up indefinitely. The risk-to-benefit ratio at five years after surgery seems acceptable, but the continued untoward effects of the bypass in the late postoperative period have led us to abandon this procedure in favor of gastric bypass. Only continued longitudinal follow-up will determine whether on balance jejunoileal bypass represents such a serious long-term health hazard that prophylactic restoration of intestinal continuity is indicated.
Previous studies have shown that the severity of enteric hyperoxaluria can be reduced in hospitalized patients who receive a diet low in oxalate and fat. Little is known of the value of such a diet in the patients' home conditions. Ten patients with hyperoxaluria (greater than 0.45 mmol/24 h) following jejuno-ileal bypass were therefore studied while on their ordinary diet and also on a diet with low-oxalate, low-fat content. The mean urinary excretion of oxalate decreased during the dietary treatment from 1.1 to 0.7 mmol/24 h. The diet was demanding, though not unfeasible for the patients. Careful and regular dietary information, preferably by a dietitian, is recommended in such cases.
Between October 1967 and November 1977, the jejunoileal bypass was performed on 177 patients for morbid exogenous obesity. The female--male ratio was 9:1. The mean follow-up period was 3.4 years and their ages ranged from 15 to 58 years. Eighty-five per cent of this patient population base were between the ages of 21 and 49 years, and in 83% the onset of obesity was in childhood. Four parameters were used to assess the effectiveness of this procedure: 1) the ponderal index, 2) the per cent of ideal weight, 3) complications, and 4) diarrhea. Using the ponderal index, 38% of the results were excellent, 20% satisfactory, and 25% poor. When the per cent of ideal weight was used, the results were 24, 27 and 32% respectively. For complications, the results were 55, 23 and 5% and with diarrhea, 53, 22 and 8%. A summary of these mean values was 42.5, 23 and 17.5% for excellent, satisfactory and poor results. There were four deaths in this series, occurring 2--16 months postoperatively, due to sepsis, pulmonary embolism, drug overdose, and liver failure. Of the 28 patients (17%) requiring revision, eight were revised for inadequate weight loss, four for excessive weight loss, 15 for uncontrollable diarrhea, and 11 for metabolic electrolyte problems. In 14% the revision was required for multiple indications. A review of 100 of these patients to determine their response to the procedure revealed that 91% were able to recommend the procedure to other patients and intrepreted their results as being excellent in 51%, good in 36% and fair in 11%. Continued use of this procedure should be deferred pending much needed investigation of the associated complications.
Hypercalciuria is common in patients who form calcium oxalate urinary stones and is considered by many to be the cause of the disorder. This review shows that there is little relationship between either the rate of stone-formation or calcium oxalate crystalluria and the urinary excretion of calcium. There is, however, a strong relationship between these parameters and the urinary excretion of oxalate which is slightly, but significantly, elevated in stone-formers compared with normals. It is concluded that this mind degree of hyperoxaluria may be much more important than hypercalciuria in the genesis of calcium oxalate stones.
In a prospective study of morbid obesity at the University of Florida, 225 consecutive patients with medical complication of obesity underwent intestinal bypass during a ten-year period from 1967 to 1977. The average age was 35 years, with the average weight being 322 lb (145 kg). Oral cholecystograms were obtained preoperatively in all patients, and repeated at one and five years postoperatively. If a patient developed symptoms, ultrasonography or a cholecystogram was performed at that time. The cumulative preoperative prevalence of cholelithiasis was 30.7 percent. The 156 patients with an intact gallbladder made up the study group. These patients have been followed for an average of 36 months, and 16 have subsequently demonstrated cholelithiasis. The post intestinal bypass incidence of cholelithiasis from surgery to the time of their last oral cholecystogram was 7.2 percent per year. Analysis of variance demonstrated no significant differences between patients, with and without cholelithiasis, with respect to serum triglycerides, cholesterol, or percent weight loss. The incidence of cholelithiasis in the morbidly obese increases further with the metabolic derangements induced by jejunoileal bypass. The increased incidence of cholelithiasis after intestinal bypass, along with the other serious metabolic sequelae that follow this procedure, suggests that the continued long-term followup of these patients is mandatory.
The effect of oral calcium on oxalate absorption was studied in eight patients with secondary hyperoxaluria after jejunoileal bypass for morbid obesity during a standardized diet with a fixed supply of fat, calcium, and oxalate. A supplementary calcium dose of 2000 mg/day reduced renal oxalate excretion from 119 to 60 mg/24 h (median values, p < 0.01). Correspondingly, 14C-oxalate absorption decreased from 28% to 9% (p < 0.01). No statistically significant increase in urinary calcium was observed. The study shows that renal oxalate excretion in patients with enteric hyperoxaluria can be reduced by oral calcium. However, we doubt that it has any practical, clinical importance.
To define those patients with upper urinary tract calculi who are more likely to have an unsuccessful outcome from extracorporeal shock-wave lithotripsy (ESWL).
A critical prospective analysis of 121 patients, referred to two university centers after ESWL had been exhausted as a treatment modality for upper urinary tract calculi, was performed. Patients were subdivided into the following groups: failure to clear fragments, failure to fragment, difficulty in calculus localization, and failure due to inherent upper urinary tract obstruction. Other important variables include the type of extracorporeal lithotriptor used, number of treatment sittings before referral, calculus location, calculus composition, patient body habitus, and the imaging leading to and associated with extracorporeal therapy.
Large renal calculi (mean, 22.2 mm) and those within dependent or obstructed portions of the collecting system were frequently referred for endoscopic management after failed ESWL. Steinstrasse can be an extremely morbid complication from ESWL and in this series was associated with irreversible loss of renal function and ureteral stricture disease. Extracorporeal lithotripsy of infectious calculi can be associated with severe septic complication. Inadequate preoperative and intraoperative imaging and morbid obesity were also associated with failure. Second- and third-generation lithotriptors were represented in greater numbers than the Dornier HM-3 in this group of ESWL failures.
ESWL remains the treatment of choice for moderately sized, uncomplicated renal calculi. Large calculi, those within obstructed or dependent portions of the collecting system, and those composed of calcium oxalate monohydrate, frequently fail ESWL. Training in the more technically challenging aspects of endoscopic lithotripsy must be encouraged.
Morbid obesity (excess body weight of 45.5 kg or 100% over ideal body weight) is associated with > 3-fold increased mortality in men and women and is resistant to dietary intervention. Gastric bypass (GBP) and vertical banded gastroplasty (VBG) are the currently accepted surgical treatments. The purpose of this study was to analyze retrospectively 153 consecutive morbidly obese patients who underwent GBP from 1975-1986 and were followed for a minimum of 5 years.
Data were analyzed from 1-16 years postoperative comparing preoperative morbidity, operative complications, postoperative morbidity, interval weight loss, maximum weight loss, and weight regain.
At the 1- and 5-year intervals, 129 and 86 patients respectively were available for review. Operative mortality was < 1%. Weight loss at 1 year = 48.5 kg rising to 57 kg at 24 months. Statistically significant weight loss of 37.0 kg (19.2 SD)(p < .001) was achieved at 5 years. The mean percent excess body weight lost was 66.4 and 50.9% at 1 and 5 years, respectively. No obesity-related deaths occurred in the follow-up period. Incidence of hypertension, cardiac disease and diabetes was reduced by 25-50% during follow-up.
GBP is a safe and effective operation which achieves sustained weight loss of > 35 kg at 5 years and reduces the complications of morbid obesity.
Patients with kidney stones are routinely advised to increase their fluid intake to decrease the risk of stone recurrence. However, there has been no detailed examination to determine whether the effect on recurrence varies by the type of beverage consumed. The authors conducted a prospective study of the relation between the intake of 21 different beverages and the risk of symptomatic kidney stones in a cohort of 45,289 men, 40-75 years of age, who had no history of kidney stones. Beverage use and other dietary information was measured by means of a semiquantitative food frequency questionnaire in 1986. During 6 years of follow-up (242,100 person-years), 753 incident cases of kidney stones were documented. After adjusting simultaneously for age, dietary intake of calcium, animal protein and potassium, thiazide use, geographic region, profession, and total fluid intake, consumption of specific beverages significantly added to the prediction of kidney stone risk (p < 0.001). After mutually adjusting for the intake of other beverages, the risk of stone formation decreased by the following amount for each 240-ml (8-oz) serving consumed daily: caffeinated coffee, 10% (95% confidence interval 4-15%); decaffeinated coffee, 10% (3-16%); tea, 14% (5-22%); beer, 21% (12-30%); and wine, 39% (10-58%). For each 240-ml serving consumed daily, the risk of stone formation increased by 35% (4-75%) for apple juice and 37% (1-85%) for grapefruit juice. The authors conclude that beverage type may have an effect on stone formation that involves more than additional fluid intake alone.
Current examples for the development of urinary stone disease are discussed by means of data from the literature and our own studies. Urinary stone disease has gained increasing significance due to changes in living conditions, i.e., industrialization and malnutrition. Changes in prevalence and incidence, the occurrence of stone types and stone location, and the manner of stone removal are explained. The importance of nutrition in the prevention of calcium oxalate stone disease is discussed in terms of fluid intake, calcium and oxalate metabolism, and dietary fat intake. The results of a study on a standardized mixed diet or an ovo-lactovegetarian diet show that well-balanced nutrition with consecutive high intake of fluids leads to a significant decrease in the risk for urinary stone formation (calculated as relative supersaturation with calcium oxalate by the computer program EQUIL).
This study assesses the long-term results of jejunoileal bypass (JIB) in 43 prospectively followed patients whose surgical bypass remained intact. Follow-up was 12.6+/-0.25 years from JIB. Weight loss and improved lipid levels, glucose tolerance, cardiac function, and pulmonary function were maintained. Adverse effects such as hypokalemia, cholelithiasis, and B12 or folate deficiency decreased over time. The incidence of diarrhea remained constant (63% vs 64% at five years), while the occurrence of hypomagnesemia increased (67% vs 43% at five years, P < 0.05). Nephrolithiasis occurred in 33% of patients. Hepatic fibrosis developed in 38% of patients and was progressive. Overall, after more than 10 years, 35% of patients appeared to benefit from JIB as defined by alleviation of preoperative symptoms and the development of only mild complications (vs 47% at five years). On the other hand, irreversible complications appeared to outweigh any benefit derived from the JIB in 19% (vs no patients at five years; P < 0.01). In summary, patients with JIB remain at risk for complications, particularly hepatic fibrosis, even into the late postoperative period.
Oxalobacter formigenes is a specific oxalate-degrading, anaerobic bacterium inhabiting the gastrointestinal tracts of vertebrates, including humans. This bacterium maintains an important symbiotic relationship with its host by regulating oxalate homeostasis, primarily by preventing enteric absorption. Increased absorption of oxalate can lead to multiple complications associated with hyperoxaluria, especially recurrent calcium oxalate urolithiasis. Detection of O. formigenes in the gastrointestinal tract has attracted attention because the absence of this bacterium appears to be a risk factor for development of hyperoxaluria and/or recurrent calcium oxalate kidney stone disease. In the present study, epidemiologic studies with patients at high risk for calcium oxalate urolithiasis showed a direct correlation between the number of recurrent kidney stone episodes and the lack of O. formigenes colonization. As expected, the lack of O. formigenes revealed a clear association with prophylactic antibiotic therapy. To confirm the importance of O. formigenes in regulating hyperoxaluria, laboratory rats known to be noncolonized were colonized with live bacteria or treated with a preparation of oxalate-degrading enzymes derived from O. formigenes to determine any subsequent increased resistance to high oxalate challenge. Rats receiving either bacteria or enzyme replacement therapy excreted far lower levels of oxalate, did not develop the crystalluria observed with control rats, and resisted the formation of calcium oxalate crystals in their nephrons. These observations, taken together, support the concept that O. formigenes is important in maintaining oxalate homeostasis, that its absence from the gut increases the risk for hyperoxaluria and recurrent kidney stone disease, and that replacement therapy is an efficient procedure to prevent hyperoxaluria and its complications.
Jejuno-ileal bypass has until recently been an accepted treatment for refractory morbid obesity. Although hyperoxaluria causing renal tract calculi is a well-recognized complication, we describe eight patients who developed significant renal failure attributable to hyperoxaluria resulting from this procedure, three requiring renal replacement therapy. We review the literature, describing 18 other cases with renal failure, the mechanisms of hyperoxaluria and its treatment. Because reversal of the bypass may result in stabilization or partial improvement of renal function, these patients require long-term follow-up of renal function.
Therapy with antibiotics in recurrent urinary tract infections may destroy colonies of Oxalobacter formigenes in the intestinal tract. A lack of oxalate degradation caused by the absence of this bacterium is suggested to contribute to the hyperabsorption of dietary oxalate and to the increase in urinary oxalate excretion. The present study was performed to evaluate the effect of recurrent urinary tract infections and subsequent changes induced in the urinary excretion profile in female calcium oxalate stone formers. Serum biochemical profiles, 24-h urinary parameters, and the personal characteristics of 57 female calcium oxalate stone patients with recurrent urinary tract infections (RUTI) were compared with 78 female calcium oxalate stone patients without a history of urinary tract infection. All subjects were recruited during the same period. In female patients with RUTI, urinary oxalate excretion was significantly higher (0.374 mmol/day) than in females without urinary tract infection (0.308 mmol/day) (P < 0.05). Moreover, the mean 24-h pH value and urinary sodium excretion were significantly higher in women with RUTI than in women without a history of urinary tract infection. The significantly higher urinary oxalate excretion in female calcium oxalate stone formers with recurrent urinary tract infections may be associated with the application of antibiotics and a subsequent temporary or permanent decolonization of Oxalobacter formigenes.
A low-calcium diet is recommended to prevent recurrent stones in patients with idiopathic hypercalciuria, yet long-term data on the efficacy of a low-calcium diet are lacking. Recently, the efficacy of a low-calcium diet has been questioned, and greater emphasis has been placed on reducing the intake of animal protein and salt, but again, long-term data are unavailable.
We conducted a five-year randomized trial comparing the effect of two diets in 120 men with recurrent calcium oxalate stones and hypercalciuria. Sixty men were assigned to a diet containing a normal amount of calcium (30 mmol per day) but reduced amounts of animal protein (52 g per day) and salt (50 mmol of sodium chloride per day); the other 60 men were assigned to the traditional low-calcium diet, which contained 10 mmol of calcium per day.
At five years, 12 of the 60 men on the normal-calcium, low-animal-protein, low-salt diet and 23 of the 60 men on the low-calcium diet had had relapses. The unadjusted relative risk of a recurrence for the group on the first diet, as compared with the group on the second diet, was 0.49 (95 percent confidence interval, 0.24 to 0.98; P=0.04). During follow-up, urinary calcium levels dropped significantly in both groups by approximately 170 mg per day (4.2 mmol per day). However, urinary oxalate excretion increased in the men on the low-calcium diet (by an average of 5.4 mg per day [60 micromol per day]) but decreased in those on the normal-calcium, low-animal-protein, low-salt diet (by an average of 7.2 mg per day [80 micromol per day]).
In men with recurrent calcium oxalate stones and hypercalciuria, restricted intake of animal protein and salt, combined with a normal calcium intake, provides greater protection than the traditional low-calcium diet.
Wernicke-Korsakoff syndrome and peripheral neuropathy are very uncommon in bariatric surgical practice. The literature indicates that these complications tend to strike patients receiving unbalanced diets or undergoing rapid weight-loss.
In a retrospective analysis of the initial experience of a bariatric team in the city of Belem, Pará, in northern Brazil, 5 cases were diagnosed in the first year, 4 of them following gastric bypass and the last one after therapy with an intragastric balloon.
All episodes followed periods of severe vomiting, which certainly interfered with intake of food as well as of routine vitamin supplements, resulting in severe polyneuropathy and other neurologic manifestions, mostly damaging motility of lower limbs. Therapy consisted of pharmacologic doses of vitamin B1 along with restoration of adequate diet and multivitamin prescriptions. Physical therapy was employed to prevent atrophy and accelerate normalization of muscle strength. All patients responded to this program after variable intervals without significant sequelae.
Thiamine-related neurologic derangements were a cause for much concern and prolonged morbidity in this series, but responded to vitamin B1 replenishment. A high degree of clinical suspicion in bariatric patients and urgent therapeutic intervention whenever postoperative vomiting persists for several days, especially during the first 2-3 months after operation, are the safest approach to these uncommon episodes. It is speculated whether peculiarities in the regional diet of this area in Brazil could have influenced the high incidence of the neurologic aberrations.
Hyperoxaluria is a major predisposing factor in calcium oxalate urolithiasis. The aim of the present study was to clarify the role of dietary oxalate in urinary oxalate excretion and to assess dietary risk factors for hyperoxaluria in calcium oxalate stone patients.
Dietary intakes of 186 calcium oxalate stone formers, 93 with hyperoxaluria (>or=0.5 mmol/day) and 93 with normal oxalate excretion (<0.4 mmol/day), were assessed by a 24-hour weighed dietary record. Each subject collected 24-hour urine during the completion of the food record. Oxalate content of foods was measured by a recently developed analytical method.
The mean daily intakes of energy, total protein, fat and carbohydrates were similar in both groups. The diets of the patients with hyperoxaluria were estimated to contain 130 mg/day oxalate and 812 mg/day calcium as compared to 101 mg/day oxalate and 845 mg/day calcium among patients without hyperoxaluria. These differences were not significant. The mean daily intakes of water (in food and beverages), magnesium, potassium, dietary fiber and ascorbic acid were greater in patients with hyperoxaluria than in stone formers with normal oxalate excretion. Multiple logistic regression analysis revealed that urinary oxalate excretion was significantly associated with dietary ascorbate and fluid intake, and inversely related to calcium intake. Differences of estimated diet composition of both groups corresponded to differences in urinary parameters.
These findings suggest that hyperoxaluria predominantly results from increased endogenous production and from intestinal hyperabsorption of oxalate, partly caused by an insufficient supply or low availability of calcium for complexation with oxalate in the intestinal lumen.
Secondary hyperoxaluria is due either to increased intestinal oxalate absorption or to excessive dietary oxalate intake. Certain intestinal diseases like short bowel syndrome, chronic inflammatory bowel disease or cystic fibrosis and other malabsorption syndromes are known to increase the risk of secondary hyperoxaluria. Although the urinary oxalate excretion is usually lower than in primary hyperoxaluria, it may still lead to significant morbidity by recurrent urolithiasis or progressive nephrocalcinosis. A clear distinction between primary and secondary hyperoxalurias is important. As correct classification may be difficult, appropriate diagnostic tools are needed to delineate the metabolic background as a basis for optimal treatment. We developed an individual approach for the evaluation of patients with suspected secondary hyperoxaluria. First, 24 h urines are examined repeatedly for lithogenic (e.g. calcium, oxalate, uric acid) and stone-inhibitory (e.g. citrate, magnesium) substances, and the patients are asked to fill in a dietary survey form. Urinary saturation is calculated using the computer based program EQUIL2, and the BONN-Risk-index is determined. The measurement of plasma oxalate and of urinary glycolate helps to distinguish between primary and secondary hyperoxalurias. If secondary hyperoxaluria is suspected, the stool is examined for Oxalobacter formigenes, an intestinal oxalate degrading bacterium, as lack or absence may lead to increased intestinal oxalate absorption. The last diagnostic step is to study the intestinal oxalate absorption using [13C2]oxalate. Depending on the results, various therapeutic options are available: 1) a diet low in oxalate, but normal or high in calcium, 2) a high fluid intake (>1.5 L/m2/d), 3) medications to increase the urinary solubility, 4) specific therapeutic measures in patients with malabsorption syndromes, depending on the underlying pathology, and 5) intestinal recolonization of Oxalobacter formigenes or the treatment with other oxalate degrading bacteria.
To emphasize the potential for Roux-en-Y gastric bypass treatment of morbid obesity to result in late development of metabolic bone disease and to illustrate the error of treating a low bone mineral density with bisphosphonates in the presence of unrecognized osteomalacia.
We conducted a retrospective case review of clinical, laboratory, and radiologic details in a patient who underwent Roux-en-Y gastric bypass as well as a review of the literature relative to metabolic bone disease associated with bariatric surgical procedures.
A 42-year-old woman was diagnosed with high bone turnover osteoporosis and failed to respond to bisphosphonate (alendronate) therapy. Her past medical history included corticosteroid-dependent asthma and a Roux-en-Y gastric bypass surgical procedure for obesity approximately 6 1/2 years before the current assessment. Evaluation revealed vitamin D deficiency in conjunction with pronounced secondary hyperparathyroidism and biochemical evidence of osteomalacia. Aggressive calcium and vitamin D supplementation corrected the vitamin D-deficient state and was accompanied by rapid improvement in clinical symptoms, biochemical variables, and bone mineral density.
This case exemplifies two principles: (1) the potential for a Roux-en-Y gastric bypass surgical procedure to lead to the development of metabolic bone disease and (2) the importance of recognizing mineralization defects as a cause for low bone mineral density, before initiation of therapy with bisphosphonates.
The Roux-en-Y gastric bypass (RYGBP) and the biliopancreatic diversion (BPD) induce long-term control of type 2 diabetes in morbidly obese individuals. The reasons for such an effect on glycemic metabolism are thought to be secondary to reduced food intake, weight loss and modifications of the enteroinsular axis which is impaired in type 2 diabetic patients. Both GLP-1 and GIP have an impaired secretin effect in type 2 diabetics, and surgery can restore this function. GIP is a peptide secreted by the duodenal K-cells in response to ingested fat and carbohydrate. In obese type 2 diabetes patients, its receptor on beta-cells is down-regulated. GLP-1 is a peptide secreted by the gut L-cells, and, in type 2 diabetes, its secretion is impaired. Both RYGBP and BPD provide durable GLP-1 delivery, both during fasting and after meal ingestion, inducing L-cell stimulation by early arrival of nutrients in the distal ileum. The secretion of GLP-1 influences glucose metabolism by inhibiting glucagon secretion, stimulating insulin secretion, delaying gastric emptying and stimulating glycogenogenesis. In conclusion, the early arrival of a meal in the terminal ileum seems to be the common feature of both operations that leads to an improvement in glycemic metabolism and to resolution of type 2 diabetes.
About 5% of the US population is morbidly obese. This disease remains largely refractory to diet and drug therapy, but generally responds well to bariatric surgery.
To determine the impact of bariatric surgery on weight loss, operative mortality outcome, and 4 obesity comorbidities (diabetes, hyperlipidemia, hypertension, and obstructive sleep apnea).
Electronic literature search of MEDLINE, Current Contents, and the Cochrane Library databases plus manual reference checks of all articles on bariatric surgery published in the English language between 1990 and 2003. Two levels of screening were used on 2738 citations.
A total of 136 fully extracted studies, which included 91 overlapping patient populations (kin studies), were included for a total of 22,094 patients. Nineteen percent of the patients were men and 72.6% were women, with a mean age of 39 years (range, 16-64 years). Sex was not reported for 1537 patients (8%). The baseline mean body mass index for 16 944 patients was 46.9 (range, 32.3-68.8).
A random effects model was used in the meta-analysis. The mean (95% confidence interval) percentage of excess weight loss was 61.2% (58.1%-64.4%) for all patients; 47.5% (40.7%-54.2%) for patients who underwent gastric banding; 61.6% (56.7%-66.5%), gastric bypass; 68.2% (61.5%-74.8%), gastroplasty; and 70.1% (66.3%-73.9%), biliopancreatic diversion or duodenal switch. Operative mortality (< or =30 days) in the extracted studies was 0.1% for the purely restrictive procedures, 0.5% for gastric bypass, and 1.1% for biliopancreatic diversion or duodenal switch. Diabetes was completely resolved in 76.8% of patients and resolved or improved in 86.0%. Hyperlipidemia improved in 70% or more of patients. Hypertension was resolved in 61.7% of patients and resolved or improved in 78.5%. Obstructive sleep apnea was resolved in 85.7% of patients and was resolved or improved in 83.6% of patients.
Effective weight loss was achieved in morbidly obese patients after undergoing bariatric surgery. A substantial majority of patients with diabetes, hyperlipidemia, hypertension, and obstructive sleep apnea experienced complete resolution or improvement.
The popularity of gastric bypass surgery for treatment of morbid obesity has been increasing in recent years. Osteomalacia and osteoporosis are commonly observed in patients who have had partial gastric resections for treatment of peptic ulcer disease. Recently, we encountered four patients with previous gastric bypass surgery who had metabolic bone disease similar to that reported in the older literature in patients who had partial gastrectomies.
Review of clinical data of four patients who developed osteomalacia and osteoporosis 9 to 12 years after gastric bypass surgery for morbid obesity.
All subjects were women, 43 to 58 years old. Three had Roux-en-Y gastric bypass, and the other had a biliopancreatic diversion 9 to 12 years prior to presentation. Weight loss averaged 41.8 kg. Patients reported fatigue, myalgias, and arthralgias. They had symptoms for many months or years before the correct diagnosis was established. All were osteopenic or osteoporotic with hypocalcemia, very low or undetectable 25-hydroxyvitamin D levels, secondary hyperparathyroidism, increased 1,25-dihydroxyvitamin D levels, and increased serum alkaline phosphatase.
Relatively little has been published in the general medical literature about this postoperative complication of bariatric surgery. Yet, nearly all patients after bariatric surgery will receive their long-term follow-up from a primary care physician. Physicians and patients need to be aware of this complication and take measures to identify and prevent it.
To describe the trends, costs, and complications associated with weight loss surgery (WLS).
Wisconsin inpatient hospital discharge data from 1990 to 2003 were used for analysis. A WLS case was defined as anyone with a WLS-related procedure code and a primary diagnosis of morbid obesity. Charges were inflation-adjusted to 2001 constant dollars; complications were defined on the basis of readmission, extended length of stay, repeat surgical procedures, or death.
The number of WLSs increased from 269 in 1990 to 1992 to 1,884 in 2000 to 2002 (rate ratio = 4.6). Increases in WLSs were greatest among those 50 to 59 years of age (rate ratio = 6.4), women (rate ratio = 6.8), and blacks (rate ratio = 20.0). Between the two periods, inflation-adjusted WLS charges increased 12-fold, and the inflation-adjusted charge per procedure doubled, despite a decreased length of stay. For 2000 to 2002, 23.3% of WLS patients had either an extended length of stay or readmission within 30 days, 7.4% required a repeat surgical procedure, and 0.7% died.
In Wisconsin, the rate and costs of WLSs have increased dramatically, and the incidence of postoperative complications was high. The epidemic of obesity in the United States makes it imperative to better assess the cost-effectiveness of WLS and to improve its safety.
A larger body size has been shown to be associated with increased excretion of urinary lithogenic solutes, and an increased risk of nephrolithiasis has been reported in overweight patients. However, the type of stones produced in these subjects has not been ascertained. Based on a large series of calculi, we examined the relationship between body size and the composition of stones, in order to assess which type of stone is predominantly favoured by overweight. Among 18,845 consecutive calculi referred to our laboratory, 2,100 came from adults with recorded body height and weight. Excluding calculi from patients with diabetes mellitus, as well as struvite and cystine stones, the study material consisted of 1,931 calcium or uric acid calculi. All calculi were analysed by infrared spectroscopy and categorized according to their main component. Body mass index (BMI) values were stratified as normal BMI (2), overweight (BMI 25–29.9) or obese (BMI≥30). Overall, 27.1% of male and 19.6% of female stone formers were overweight, and 8.4 and 13.5% were obese, respectively. In males, the proportion of calcium stones was lower in overweight and obese groups than in normal BMI group, whereas the proportion of uric acid stones gradually increased with BMI, from 7.1% in normal BMI to 28.7% in obese subjects (PP=0.003). In addition, the proportion of uric acid stones markedly rose with age in both genders (P
Roux-en-Y gastric bypass (RYGBP) is more efficient than adjustable gastric banding (AGB) in weight loss and relieving co-morbidities, but nutritional complications of each surgical procedure have been poorly evaluated.
A cross-sectional study was performed to compare nutritional parameters in 201 consecutive obese patients, who had been treated either by conventional behavioral and dietary therapy (CT, n=110) or by bariatric surgery, including 51 AGB and 40 RYGBP.
BMI was similar after AGB (36.6 +/- 5.3 kg/m2) and RYGBP (35.4 +/- 6.3 kg/m2), but patients in the RYGBP group had lost more weight and had less metabolic disturbances than those in the AGB group. On the other hand, the prevalence of nutritional deficits was significantly higher in the RYGBP group than in the 2 other groups (P<0.01), whereas the AGB group did not differ from CT. Particularly, the RYGBP group presented an unexpected high frequency of deficiencies in fat-soluble vitamins. Moreover, vitamin B12, hemoglobin, plasma prealbumin and creatinine concentrations were low in the RYGBP group.
RYGBP is more efficient than AGB in correcting obesity, but this operation is associated with a higher frequency of nutritional deficits that should be carefully monitored.