Johansen KL, Young B, Kaysen GA, Chertow GM. Association of body size with outcomes among patients beginning dialysis. Am J Clin Nutr 80: 324
Although obesity confers an increased risk of mortality in the general population, observational reports on the dialysis population have suggested that obesity is associated with improved survival. These reports have generally not examined extremely high values of body mass index (BMI; in kg/m(2)), survival >1 y, or alternative measures of adiposity.
We sought to clarify the relation between body size and outcomes among a large cohort of patients beginning dialysis.
Data on 418 055 patients beginning dialysis between 1 April 1995 and 1 November 2000 were analyzed by using US Renal Data System data. BMI was divided into 8 categories in increments of 3 units, ranging from < 19 to > or =37, and the relation between survival and BMI was examined by using proportional hazards regression with adjustment for demographic, laboratory, and comorbidity data.
High BMI was associated with increased survival in this cohort, even at extremely high BMI, after adjustment, and over a 2-y average follow-up time. This was true for whites, African Americans, and Hispanics but not for Asians. High BMI was also associated with a reduced risk of hospitalization and a lower rate of mortality in all mortality categories. Alternative estimates of adiposity, including the Benn index and estimated fat mass, yielded similar results, and adjustments for lean body mass did not substantially alter the findings.
High BMI is not associated with increased mortality among patients beginning dialysis. This finding does not appear to be a function of lean body mass and, although modified by certain patient characteristics, it is a robust finding.
Available from: Hirotaka Fukasawa
- "These observations suggest that muscle mass is an important predictor of mortality in HD patients. However, increased fat mass has been associated with a lower risk of mortality and a reduced risk of hospitalization in HD patients . Moreover, Kakiya et al.  showed that a decrease in body fat is associated with an increased risk of death in these patients. "
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ABSTRACT: Malnutrition is highly prevalent and contributes to mortality in hemodialysis (HD) patients. Although the receptor for advanced glycation end products (RAGE) system also contributes to the morbidity and mortality of these patients, the role that the RAGE system plays in determining nutritional status is currently unknown.
A cross-sectional study examining 79 HD patients was performed. The plasma concentrations of the soluble RAGE (sRAGE) and S100A12 (also known as EN-RAGE) were studied to evaluate their association with nutritional status, which was assessed by measuring the mid-thigh muscle mass and subcutaneous fat mass with computed tomography.
Plasma S100A12 concentrations were shown to be significantly and negatively correlated with muscle mass and with fat mass (r = −0.237, P < 0.05 and r = −0.261, P < 0.05, respectively). In contrast, sRAGE was not shown to significantly correlate with either of these factors. Multiple regression analyses demonstrated that S100A12 is a significant independent predictor of both muscle mass and fat mass (P < 0.01 and P < 0.05, respectively).
Our findings suggest that plasma S100A12 levels could play an important role in determining muscle mass and fat mass in HD patients.
Study number; UMIN000012341.
Available from: Juan Jesus Carrero
- "Although some epidemiological studies have suggested a benefit of obesity on clinical outcomes in CKD patients [5e7], these findings are controversial depending on several factors such as dialysis modality , length of follow-up  , ethnicity , and the amount of lean body mass  , making difficult the understanding of the real impact of obesity on outcomes in CKD population. The use of BMI as a marker of obesity may be the potential reason for such divergent results . "
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ABSTRACT: Background and aim:
Cardiovascular disease is the leading cause of death among patients with chronic kidney disease (CKD). Although there is emerging evidence that excess visceral fat is associated with a cluster of cardiometabolic abnormalities in these patients, the impact of visceral obesity evaluated by a gold-standard method on future outcomes has not been studied. We aimed to investigate whether visceral obesity assessed by computed tomography was able to predict cardiovascular events in CKD patients.
Methods and results:
We studied 113 nondialyzed CKD patients [60% men; 31% diabetics; age 55.3 ± 11.3 years; body mass index (BMI) 27.2 ± 5.3 kg/m(2); estimated glomerular filtration rate (GFR) 33.7 ± 13.6 ml/min/1.73 m(2)]. Visceral and subcutaneous abdominal fat were assessed by computed tomography at L4-L5. Visceral to subcutaneous fat ratio >0.55 (highest tertile cut-off) was defined as visceral obesity. Cardiovascular events including acute myocardial infarction, angina, arrhythmia, uncontrolled blood pressure, stroke and cardiac failure were recorded during 24 months. Cardiovascular events were 3-fold higher in patients with visceral obesity than in those without visceral obesity. The Kaplan-Meier analysis indicated that patients with visceral obesity had shorter cardiovascular event-free time than those without visceral obesity (P = 0.021). In the univariate Cox analysis, visceral obesity was associated with higher risk of cardiovascular events (hazard ratio = 3.4; 95% confidence interval = 1.1-10.5; P = 0.03). The prognostic power of visceral obesity for cardiovascular events remained significant after adjustments for sex, age, diabetes, previous cardiovascular disease, smoking, sedentary lifestyle, BMI, GFR, hypertension, dyslipidemia and inflammation.
Visceral obesity assessed by computed tomography was a predictor of cardiovascular events in CKD patients.
Available from: Cristiane Ferreira Moraes
- "Nutrition xxx (2012) 1–5 and, according to the World Health Organization (WHO) , subjects with a BMI lower than 18.5 kg/m 2 are considered underweight. Studies have shown that a low BMI (according to the WHO classification) is a predictor of a poor outcome and a high death risk  , although overweight and obesity are associated with a better survival in patients on HD  . However, the inability of BMI to distinguish muscle mass from fat mass (FM) is well documented  . "
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ABSTRACT: To evaluate the body composition and inflammatory status in patients on hemodialysis (HD) according to the cutoff of 23 kg/m² for the body mass index (BMI).
Forty-seven patients (30 men, 11 diabetics, 53.8 ± 12.2 y of age, 58.2 ± 50.9 mo on HD) were studied. Anthropometric data and handgrip strength were evaluated. C-reactive protein, tumor necrosis factor-α, leptin, and interleukin-6 were measured. Mortality was assessed after 24 mo of follow-up.
Nineteen patients (40.4%) presented BMI values lower than 23 kg/m² and leptin levels, midarm muscle area, and free-fat mass were significantly lower in these patients. The prevalence of functional muscle loss according to handgrip strength was not different between the BMI groups. The sum of skinfold thicknesses, the percentage of body fat, fat mass, the fat mass/free-fat mass ratio, and waist circumference were significantly lower in patients with a BMI lower than 23 kg/m², but the mean values did not indicate energy wasting. Patients with a BMI higher than 23 kg/m² presented a higher prevalence of inflammation and higher waist circumference and body fat values. The adiposity parameters were correlated with C-reactive protein and leptin. A Cox multivariate regression analysis demonstrated that C-reactive protein, tumor necrosis factor-α, and interleukin-6 predict cardiovascular mortality.
Patients on HD with a BMI lower than 23 kg/m² did not present signs of energy wasting, whereas those with a BMI higher than 23 kg/m² had more inflammation, probably because of a greater adiposity. Thus, the BMI value of 23 kg/m² does not seem to be a reliable marker of protein-energy wasting in patients on HD.
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