Inflammation Modifies the Paradoxical Association between Body Mass Index and Mortality in Hemodialysis Patients

Abstract

High body mass index (BMI) is paradoxically associated with better outcome in hemodialysis (HD) patients. Persistent inflammation commonly features in clinical conditions where the obesity paradox is described. We examined the relationship between BMI and mortality in HD patients, accounting for inflammation, in a historic cohort study of 5904 incident HD patients enrolled in 2007-2009 (312 facilities; 15 European countries) with $3 months of follow-up. Patients were classified by presence (n=3231) or absence (n=2673) of inflammation (C-reactive protein $10 mg/l and/or albumin #35 g/l). Patients were divided into quintiles by 21.5,and .29.8 kg/m 2 , respectively). Noninflamed patients in BMI Q5 formed the reference group. During a median follow-up period of 36.7 months, 1929 deaths occurred (822 cardiovascular), with 655 patients censored for renal transplantation and 1183 for loss to follow-up. Greater mortality was observed in inflamed patients (P,0.001). In fully adjusted time-dependent analyses, the all-cause mortality risk in noninflamed patients was higher only in the lowest BMI quintile (hazard ratio [HR, 1.80 . Thus, whereas a protective effect of high BMI was observed in inflamed patients, this effect was mitigated in noninflamed patients.

The Obesity Paradox and the Role of Inflammation

“…The findings of this paper, using observational data, suggest that weight loss may have potential advantages for obese patients on dialysis without evidence of inflammation. 8 This finding should be confirmed in intervention studies before incorporation into clinical practice.…”

“…3 In this issue of the Journal of the American Society of Nephrology (JASN), results of a large cohort study have shown a novel important aspect of obesity-the effect modification by inflammation. 8 Stenvinkel et al 8 found that the paradoxical association between BMI and mortality in patients that required hemodialysis was modified by inflammation. Stenvinkel et al 8 studied 5904 patients with incident hemodialysis from 15 European countries that were enrolled in the study in 2007-2009.…”

“…8 Stenvinkel et al 8 found that the paradoxical association between BMI and mortality in patients that required hemodialysis was modified by inflammation. Stenvinkel et al 8 studied 5904 patients with incident hemodialysis from 15 European countries that were enrolled in the study in 2007-2009. Patients were divided into quintiles by BMI and stratified by the presence or absence of inflammation.…”

“…The article by Stenvinkel et al 8 that is in this issue of JASN brings weight management of obese patients on dialysis into context. What can be learned?…”

“…The article by Stenvinkel et al 8 also provides important advice for underweight patients. As the article points out, underweight patients on dialysis represent a high-risk population.…”