[Show abstract][Hide abstract] ABSTRACT: Purpose
We examine kidney stone disease as a potential risk factor for chronic kidney disease, end stage kidney disease and treatment with dialysis.
Materials and Methods
The NHANES (National Health and Nutrition Examination Survey) 2007-2010 database was interrogated for patients with a history of kidney stones. Demographics and comorbid conditions including age, gender, body mass index, diabetes, hemoglobin A1c, hypertension, gout and smoking were also assessed. Multivariate analysis adjusting for patient demographics and comorbidities was performed to assess differences in the prevalence of chronic kidney disease and treatment with dialysis between the 2 groups. History of nephrolithiasis was assessed with the question, “Have you ever had kidney stones?” Chronic kidney disease was defined as an estimated glomerular filtration rate of less than 60 ml/minute/1.73 m2 and/or a urinary albumin-to-creatinine ratio greater than 30 mg/gm. Statistical calculations were performed using Stata® software with determinations of p values and 95% CI where appropriate.
The study included an analysis of 5,971 NHANES participants for whom data on chronic kidney disease and kidney stones were available, of whom 521 reported a history of kidney stones. On multivariate analysis a history of kidney stones was associated with chronic kidney disease and treatment with dialysis (OR 1.50, 1.10–2.04, p = 0.013 and OR 2.37, 1.13–4.96, p = 0.025, respectively). This difference appeared to be driven by women, where a history of kidney stones was associated with a higher prevalence of chronic kidney disease (OR 1.76, 1.13–2.763, p = 0.016) and treatment with dialysis (OR 3.26, 1.48–7.16, p = 0.004). There was not a significant association between kidney stone history and chronic kidney disease or treatment with dialysis in men.
Kidney stone history is associated with an increased risk of chronic kidney disease and treatment with dialysis among women even after adjusting for comorbid conditions. Large scale prospective studies are needed to further characterize the relationship between nephrolithiasis and chronic kidney disease.
The Journal of Urology. 11/2014; 192(5):1440–1445.
[Show abstract][Hide abstract] ABSTRACT: and Objectives: To examine kidney stone disease as a potential risk factor for chronic kidney disease (CKD), end-stage kidney disease and treatment with dialysis (ESKD).
[Show abstract][Hide abstract] ABSTRACT: Encrusted ureteral stents are a challenging endourologic problem that may require multiple procedures. We performed a multi-institutional review of percutaneous nephrolithotomy (PCNL) as primary treatment for encrusted stents.
Patients were identified who underwent percutaneous nephrolithotomyPCNL for treatment of an encrusted ureteral stent. Retrospective review was performed to compile details of procedures and outcomes.
Thirty-eight renal units underwent percutaneous nephrolithotomyPCNL for encrusted ureteral stents in 36 patients. Mean age was 47.1 years (±16.7) and female: male ratio was 15:21. Mean stent indwelling time prior to removal was 28.2 months (±27.8). Reason for long indwelling time was reported in 25 cases and included "patient unaware stent needed to be removed" (17 cases), pregnancy (2 cases), other comorbidities (3 cases), and patient was a prisonerincarceration (3 cases). In 3 cases, the stent had become encrusted within 3 months of placement. Mean operative time was 162 minutes (±71). There were no major intraoperative complications and no patients required blood transfusion. Litholopaxy was required for bladder coil encrustations in 22 cases (58%) and ureteroscopy with lithotripsy was required for encrustation of the ureteral portion of the stent in 13 cases (34.2%). Second look percutaneous procedures were required in 13 cases (34.2%). Stent was removed at the time of PCNL without need for concomitant or delayed ureteroscopy and/or cystolitholapaxy in 8 (21%). Ultimately, all stents were removed successfully. Patients were rendered radiographically stone-free in 24 cases (63%).
In this multi-center review, PCNL is confirmed to be a safe and effective means of addressing the retained and encrusted ureteral stent. Percutaneous nephrolithotomyPCNL without ureteroscopy or litholopaxy was sufficient in a minority of cases (21%). Adjunctive endourologic modalities are often required, and the surgeon should anticipate the need for concomitant antegrade ureteroscopic laser lithotripsy and/or cystolitholapaxy. Although complete stent removal can be anticipated, residual fragments are not uncommon.
Journal of endourology / Endourological Society 04/2014; · 1.75 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objective: To evaluate the cost effectiveness of shock wave lithotripsy (SWL) versus ureteroscopic lithotripsy (URS) for patients with renal stones less than 1.5 cm in diameter. Methods: Patient age, stone diameter, stone location, and stone free status were recorded for patients treated with SWL or URS for renal stones under 1.5 cm in maximal diameter over a one year period. Institutional charges were obtained from in-house billing. A decision analysis model was constructed to compare the cost-effectiveness of SWL and URS and using our results and success rates for modeling. Three separate models were created to reflect practice patterns for shock wave lithotripsy. Results: One hundred fifty-eight patients were included in the study - 78 underwent SWL and 80 underwent URS as primary treatment. Single procedure stone free rates for SWL and URS were 55% and 95% respectively (p<0.0001). Decision analysis modeling demonstrated cost effectiveness of SWL when SWL single procedure stone free rates (SFR) were 65-67% or when URS single procedure SFR was 72-84%. Conclusions: This retrospective study revealed superior SFR results for renal stones under 1.5cm for URS compared to SWL. Our decision analysis model demonstrates that for SWL stone free rates less than 65-67% or for URS stone free rates greater than 72-84%, SWL is not a cost-effective treatment option. Based on these findings, careful stratification and selection of stone patients may enable surgeons to increase the cost effectiveness of SWL.
Journal of endourology / Endourological Society 01/2014; · 1.75 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Introduction
Flexible ureteroscopy (URS) is rapidly becoming a first-line therapy for many with renal and ureteral stones. However, the present understanding of treatment outcomes for patients with isolated proximal ureteral stones is limited. Therefore, we performed a prospective, multi-institutional study of ureteroscopic management of proximal ureteral stones < 2 cm in order to better define clinical outcomes associated with this approach.
Adult patients with proximal ureteral calculi < 2 cm were prospectively identified. Patients with concomitant ipsilateral renal calculi or prior ureteral stenting were excluded. Flexible URS, Holmium laser lithotripsy, and ureteral stent placement was performed. Ureteral access sheath use, laser settings, and other details of peri- and postoperative management were based on individual surgeon preference. Stone clearance was determined by renal ultrasound and KUB results at 4–6 weeks postoperatively.
Of 71 patients, 44 (62%) were male and 27 (38%) were female. Mean age was 48.2 years. ASA score was 1 in 12 (16%), 2 in 41 (58%), 3 in 16 (23%), and 4 in 2 (3%). Mean BMI was 31.8 kg/m2. Mean stone size was 7.4mm (5-15). Mean surgical time was 60.3 minutes (15-148). Intraoperative complications occurred in 2 (2.8%) including mild ureteral trauma. Postoperative complications occurred in 6 (8.7%) including UTI (3), urinary retention (2), and flash pulmonary edema (1). The stone-free rate was 95%; for stones <1cm, the stone-free rate was 100%.
Flexible URS is associated with excellent clinical outcomes and acceptable morbidity when applied to patients with proximal ureteral stones < 2 cm.
[Show abstract][Hide abstract] ABSTRACT: To evaluate the relationship between serum c-reactive protein and lifetime kidney stone prevalence.
A cross sectional study of particpants from the Continuous National Health and Nutrition Examination Survey (NHANES) from years 2007-2008 and 2008-2009 was performed. Data were available for 11,033 participants.
On univariate analysis, a strong correlation exists between CRP quintile and kidney stone history. After adjusting for known confounders, multivariate logistic regression demonstrated a significant relationship between CRP and lifetime prevalence of kidney stones in younger persons (age 20-39, p value for trend = 0.002). For persons aged 20-39, lifetime prevalence of kidney stones increased with increasing CRP quintile (p = 0.002 for trend). Specifically, those in the 3(rd) (OR 3.86, 95% CI 1.07 to 13.88, p = 0.04) and 5(th) quintiles (OR 3.85, 95% CI 1.46 to 10.17, p = 0.009). The fourth quintile of CRP approached statistical significance (OR 2.56, 95% CI 0.96 to 6.81, p = 0.059). The relationship between CRP and kidney stone history was not significant in older age groups (40-59 and 60+).
There exists a significant relationship between serum CRP and self-reported kidney stones in younger persons. This may shed light on potential mechanisms of stone formation in this age group and help gain a better understanding of mediators of stone risk. Further studies are necessary to understand the mechanisms which underly these epidemiologic findings.
The Journal of urology 09/2013; · 3.75 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Since its introduction into the endourologist's armamentarium almost 40 years ago, percutaneous nephrolithotomy (PCNL) has become the standard of care for patients with large-volume nephrolithiasis. Postoperative infection is one of the most common complications of the procedure, and postoperative sepsis is one of the most detrimental. A number of factors have been found to increase the risk of postoperative sepsis. These include patient characteristics that are known preoperatively, such as urine culture obtained from the bladder or from the renal pelvis if percutaneous access to the renal pelvis is obtained in advance to the procedure. Neurogenic bladder dysfunction secondary to spinal cord injury and anatomical renal abnormalities, such as pelvicalyceal dilatation, have also been associated with increased incidence of fever and sepsis after the procedure. Several intraoperative factors, such as the average renal pressure sustained during PCNL and the operative time, also seem to increase the risk of sepsis. Finally, the contribution of postoperative factors, such as presence of a nephrostomy tube or a urethral catheter, has also been investigated. A short preoperative course of antibiotics has been found to significantly decrease the rate of postoperative fever and sepsis. Novel agents targeted at sepsis prevention and treatment, such as anti-endotoxin antibodies and cholesterol-lowering drugs statins, are currently under investigation.
[Show abstract][Hide abstract] ABSTRACT: Kidney stone disease is common and may be associated with an increased risk of coronary heart disease (CHD). Previous studies of the association between kidney stones and CHD have often not controlled for important risk factors, and the results have been inconsistent.
To examine the association between a history of kidney stones and the risk of CHD in 3 large prospective cohorts.
A prospective study of 45,748 men and 196,357 women in the United States without a history of CHD at baseline who were participants in the Health Professionals Follow-up Study (HPFS) (45,748 men aged 40-75 years; follow-up from 1986 to 2010), Nurses' Health Study I (NHS I) (90,235 women aged 30-55 years; follow-up from 1992 to 2010), and Nurses' Health Study II (NHS II) (106,122 women aged 25-42 years; follow-up from 1991 to 2009). The diagnoses of kidney stones and CHD were updated biennially during follow-up.
Coronary heart disease was defined as fatal or nonfatal myocardial infarction (MI) or coronary revascularization. The outcome was identified by biennial questionnaires and confirmed through review of medical records. RESULTS Of a total of 242,105 participants, 19,678 reported a history of kidney stones. After up to 24 years of follow-up in men and 18 years in women, 16,838 incident cases of CHD occurred. After adjusting for potential confounders, among women, those with a reported history of kidney stones had an increased risk of CHD than those without a history of kidney stones in NHS I (incidence rate [IR], 754 vs 514 per 100,000 person-years; multivariable hazard ratio [HR], 1.18 [95% CI, 1.08-1.28]) and NHS II (IR, 144 vs 55 per 100,000 person-years; multivariable HR, 1.48 [95% CI, 1.23-1.78]). There was no significant association in men (IR, 1355 vs 1022 per 100,000 person-years; multivariable HR, 1.06 [95% CI, 0.99-1.13]). Similar results were found when analyzing the individual end points (fatal and nonfatal MI and revascularization).
Among the 2 cohorts of women, a history of kidney stones was associated with a modest but statistically significantly increased risk of CHD; there was no significant association in a separate cohort of men. Further research is needed to determine whether the association is sex-specific.
JAMA The Journal of the American Medical Association 07/2013; 310(4):408-15. · 29.98 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Abstract Objectives: To examine the clinical outcomes and cost-effectiveness of endourologic procedures performed in the office using standard fluoroscopy and topical anesthesia. Methods: We performed a retrospective review of all patients who underwent primary ureteral stent placement, ureteral stent exchange, or ureteral catheterization with retrograde pyeolography or Bacillus Calmette-Guerin (BCG) instillation under fluoroscopic guidance in the office. For an evaluation of potential time savings, we compared this to a cohort of similar procedures performed in the operating room during the same time period. Results: Procedures were attempted in 65 renal units in 38 patients (13 male, 25 female) with a mean age of 62.2 years (range 29.1-95.4 years). Primary ureteral stent placement was successful in 23/24 (95.8%) renal units. Ureteral stent exchange was successful in 19/22 (86.4%) renal units. Ureteral catheterization with retrograde pyelography or BCG instillation was successful in 19/19 (100%) renal units. The total cost savings for the 38 patients in this study, including excess cost from failure in the office, was approximately $91,496, with an average cost savings of $1,551 per procedure. Office-based procedures were associated with a nearly three-fold reduction in total hospital time as a result of reduced periprocedure waiting times. Conclusions: Ureteral stent placement, ureteral stent exchange, and ureteral catheterization can be performed safely and effectively in the office in both men and women. This avoids general anesthesia and provides significant savings of time and cost for both patients and the health care system.
Journal of endourology / Endourological Society 05/2013; 27(5):662-6. · 1.75 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Abstract Purpose: We examined the stone composition, 24-hour urinary risk factors, and insurance status in patients evaluated in two regional stone clinics to further investigate the relationship between the socioeconomic status and kidney stone formation. Materials and Methods: We performed a retrospective review of stone formers who completed a 24-hour urinalysis as part of a metabolic evaluation for nephrolithiasis. Insurance status was determined by billing records and those with state-assisted insurance (SAI) were compared to patients with private insurance (PI). Multivariate analyses were performed adjusting for known risk factors for stones. Results: Three hundred forty-six patients were included. Patients with SAI (16%) were significantly more likely to be female (55% vs.38%, p=0.026) and younger (43.5 vs.49.2, p=0.003). Among those with stone composition data (n=200), SAI patients were as likely to form calcium phosphate (CaPhos) as calcium oxalate (CaOx) stones (46.9% vs.31.3%, p=0.44). PI patients were significantly less likely to form CaPhos than CaOx stones (10.1% vs.77.4%, p<0.001). On multivariate analysis, among those with calcium stones, the odds of forming CaPhos stones over CaOx stones were ten times higher among SAI patients compared to PI, odds ratio 10.2 (95% CI 3.6, 28.6, p<0.001). Further, patients with SAI had significantly higher urine sodium, pH, and supersaturation of CaPhos, and a lower supersaturation of uric acid compared to patients with PI. Conclusions: SAI was associated with a greater likelihood of a CaPhos stone composition and increased urinary risk factors for CaPhos stones. These findings may reflect dietary or other unmeasured differences, and have important implications for resource allocation and counseling, as treatment may differ for these groups.
Journal of endourology / Endourological Society 02/2013; · 1.75 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This article reviews the data on pharmacologic treatment of kidney stone disease, with a focus on prophylaxis against stone recurrence. One of the most effective and important therapies for stone prevention, an increase in urine volume, is not discussed because this is a dietary and not a pharmacologic intervention. Also reviewed are medical expulsive therapy used to improve the spontaneous passage of ureteral stones and pharmacologic treatment of symptoms associated with ureteral stents. The goal is to review the literature with a focus on the highest level of evidence (ie, randomized controlled trials).
Urologic Clinics of North America 02/2013; 40(1):21-30. · 1.39 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This study aimed to characterize the urinary tract stones in phantom and patients using single-source dual-energy computed tomography.
Twenty stones of pure crystalline composition (uric acid [UA], struvite, cystine, and calcium oxalate monohydrate) were assessed in a phantom and 11 patients (age 39-67 years) with urinary tract stones were evaluated. An initial low-dose unenhanced CT (tube potential, 120 kilovolts [peak]; milliampere range, 150-450; noise index, 26; section thickness, 5 mm) followed by a targeted dual-energy computed tomography acquisition on a single-source dual-energy computed tomography (Discovery CT 750 HDCT, GE) was performed. Uric acid and non-UA stones were defined using a 2-material decomposition (material density-iodine/water) algorithm. The stone effective atomic number (Zeff) was used to subclassify non-UA stones. The stone attenuation (Hounsfield unit) was also studied to determine its performance in predicting the composition. Ex vivo chemical analysis of the stone served as a criterion standard.
Of the 59 verified stones (phantom, 20; patients, 39; mean size, 6 mm), there were 16 UA and 43 non-UA type. The material density images were 100% sensitive and accurate in detecting UA and non-UA stones. The Zeff accurately stratified struvite, cystine, and calcium (calcium oxalate monohydrate) stones in the phantom. In patients, Zeff identified 83% of calcium stones (n = 24), and in stones of mixed type, it resembled dominant composition. The Hounsfield unit measurements alone were 71% sensitive and 69% accurate in detecting the UA stones.
Single-source dual-energy computed tomography can accurately predict UA and non-UA stone composition in vitro and in vivo. Substratification of non-UA stones of pure composition can be made in vitro and in vivo. In stones of mixed composition, the Zeff values reflect the dominant composition.
[Show abstract][Hide abstract] ABSTRACT: Aims: Although it is thought that renal colic results from urinary tract obstruction, some patients evaluated for renal colic are found to have no source for their pain other than small, non-obstructing renal calyceal stones. We refer to this as "the small stone syndrome". We aim to determine if small non-obstructing calyceal stones may also cause pain and that treatment may relieve this pain. Method: A retrospective chart review was performed to identify patients with non-obstructing calyceal stones (≤ 4 mm in diameter) evaluated for flank pain and treated by ureteroscopy. Patients completed a follow-up questionnaire regarding pre- and postoperative pain and quality of life (QOL). Results: 13 patients were included in the analysis. Mean stone diameter was 3 mm (range 1.5 - 4.0 mm). Following ureteroscopy, 11 (85%) patients reported complete resolution of pain and 2 (15%) reported partial resolution. 12 patients were able to describe preoperative and postoperative QOL and of these, 8 (67%) had improved QOL, 4 (33%) had no change, and none reported worsening. Follow-up imaging was available in 10 patients: stone free in 6 (60%), reduction in stone size in 3 (30%), and stone unchanged in 1 (10%). Conclusions: Ureteroscopic treatment of painful small, non-obstructing renal calyceal stones achieved complete or partial resolution of pain in all patients and improvement in QOL in a majority of patients.
European Urology 01/2013; 63(1):182. · 10.48 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: PURPOSE: To evaluate the cost-effectiveness of anti-retropulsion devices used during ureteroscopic lithotripsy. METHODS: A decision analysis model was constructed to compare the cost-effectiveness of ureteroscopic lithotripsy with and without an anti-retropulsion device. Risk of stone retropulsion was determined from published data in the English literature. Expected value calculations were used to determine whether the additional cost of a device was cost-effective in preventing secondary procedures to treat retropulsed stones. Device cost was determined by using the average cost of all commercially available devices. RESULTS: Economically, it becomes cost-effective to use an anti-retropulsion device at or above a retropulsion rate of 6.3%. The weighted probability of retropulsion with vs. without an anti-retropulsion device was 98.1% and 83.7% respectively. Estimated costs of secondary procedures, SWL and ureteroscopy, needed to treat retropulsed stones were $5,290 (SWL) and $6,390 (ureteroscopy) respectively whereas the average cost of a device is $278. Thus, the average additional cost of ureteroscopic lithotripsy with an anti-migration device is $384 versus $952 without the use of an anti-migration device. CONCLUSIONS: It is cost-effective to use an anti-retropulsion device for retropulsion rates greater than 6.3%.
The Journal of urology 11/2012; · 3.75 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To examine differences in 24-hour urine composition between recurrent and first-time stone-formers.
A retrospective review of patients evaluated in 2 metabolic stone clinics was performed. Recurrent stone formation was defined as patients with a history of more than 1 stone episode and first-time stone-formers were those with a history of a single-stone episode. Frequencies of urine metabolic abnormalities were noted. Multivariate linear regression was performed to evaluate the likelihood of abnormalities of 24-hour urine composition.
Three-hundred eleven patients met inclusion criteria: 71 (22.8%) were first-time stone-formers and 240 (77.1%) were recurrent stone-formers. On univariate analysis, the likelihood of having a single abnormality of 24-hour urine composition (ie, hypercalciuria, hyperoxaluria, hyperuricosuria, or hypocitraturia) was similar between the 2 groups (83.1% for first-time vs 88.8% for recurrent, P = NS). In addition, there were similar rates of hypercalciuria (39.4% vs 43.3%, P = NS), hyperoxaluria (32.4% vs 33.3%, P = NS), hyperuricosuria (29.6% vs 23.3%, P = NS), and hypocitraturia (45.0% vs 45.0%, P = NS). On multivariate logistic regression, there was no difference in detection of any urine abnormality (ie, hypercalciuria or hyperoxaluria or hypocitraturia or hyperuricosuria) between first-time (referent) or recurrent stone-formers (OR 1.68, 95% CI .8-3.5, P = .2).
In this study, detection of urine abnormalities was similar in first-time and recurrent stone-formers. Given the strong patient preference for stone prevention and the high success of directed therapy in the literature, we believe it is not unreasonable to offer comprehensive metabolic evaluation to first-time stone-formers who express a desire to undergo evaluation.