Abstract
BackgroundAlthough elevated body mass index (BMI) is a predictor of better clinical outcomes in dialysis patients, the evidence in pre-dialysis chronic kidney disease (CKD) is conflicting. Clinical measures of central obesity may be better prognostic indicators, although investigation has been limited. The aim of this study was to assess the predictive value of anthropometric measures for kidney failure progression and mortality in stage 3–4 CKD.MethodsThe study included newly referred stage 3–4 CKD patients at a single centre between 1/1/2008 and 31/12/2010. The associations between clinical measures of obesity (BMI, waist circumference [WC] and conicity index [ConI]) and time to a composite primary outcome of doubling of serum creatinine, commencement of renal replacement therapy or mortality were evaluated using the Kaplan-Meier method and multivariable Cox regression models.ResultsOver a median follow-up period of 3.3 years, 229 (25.4 %) patients of a total population of 903 experienced the composite primary renal outcome. When compared to normal BMI (18.5-24.9 kg/m2, n = 174), the risk of the composite primary outcome was significantly lower in both the overweight (BMI 25–29.9 kg/m2, n = 293; adjusted hazard ratio [HR] 0.50, 95 % CI 0.33-0.75) and obese class I/II groups (BMI 30–39.9 kg/m2, n = 288; HR 0.62, 95 % CI 0.41-0.93), but not in the obese class III group (BMI ≥40 kg/m2, n = 72; HR 0.94, 95 % CI 0.52-1.69). All-cause mortality was also lower in the overweight group (HR 0.50, 95 % CI 0.30-0.83). WC and ConI were not associated with either the composite primary outcome or mortality.ConclusionBMI in the overweight range is associated with reduced risks of kidney disease progression and all-cause mortality in stage 3–4 CKD. WC and ConI were not independent predictors of these outcomes in this population.Electronic supplementary materialThe online version of this article (doi:10.1186/s12882-016-0290-y) contains supplementary material, which is available to authorized users.
Highlights
Elevated body mass index (BMI) is a predictor of better clinical outcomes in dialysis patients, the evidence in pre-dialysis chronic kidney disease (CKD) is conflicting
The aim of this study was to investigate the associations between baseline anthropometric measures of body size (BMI, waist circumference (WC) and conicity index (ConI)) and the clinical outcomes of kidney disease progression and all-cause mortality in incident Australian adults with stage 3–4 CKD referred to a specialist renal service
While a high ConI was predictive of the composite renal outcome in unadjusted models, neither WC nor ConI showed a significant association with kidney disease progression or mortality in adjusted models
Summary
Elevated body mass index (BMI) is a predictor of better clinical outcomes in dialysis patients, the evidence in pre-dialysis chronic kidney disease (CKD) is conflicting. A recent cohort study of 453,946 United States veterans with an estimated glomerular filtration rate (eGFR) < 60 ml/min per 1.73m2observed a consistent, U-shaped association between BMI and the outcomes of kidney disease progression and mortality, with the best outcomes observed in overweight and mildly obese subjects [8] This risk factor paradox has been deemed by some as “reverse causation”, implying that there is unintentional illness-related weight loss which contributes to higher mortality [9]. Despite being a clinical tool which is widely used to assess obesity, BMI is an unreliable measure of body fat content in patients with CKD [10] This measure is unable to differentiate between muscle and fat amount and distribution, and, while having reasonable correlation with body fat percentage, BMI has poor sensitivity for diagnosing obesity [11]. These limitations are concerning in light of the increasing evidence that abdominal obesity is a key contributor to the health risks associated with obesity [12]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
