Body Mass Index-Mortality Paradox in Hemodialysis Patients

Abstract

See related article, pp 1014–1020 In the general population, there is a clear association between body mass index (BMI) and mortality.1 However, in hemodialysis patients, a number of clinical studies have demonstrated that BMI is inversely related to mortality.2,3 The explanation for this interesting paradox is unknown. In this edition of the journal, Agarwal4 conducted a cross-sectional analysis of 368 dialysis patients in his practice where he determined BMI and gathered demographic and clinical factors. In addition, he used ambulatory blood pressure monitoring after the first or midweek hemodialysis session for 44 hours and measured 2D and M-mode echocardiograms and inferior vena cava diameter. During a total of 1122 patient-years of cumulative follow-up (median: 2.7 years), 119, or 32%, of these patients died.4 He observed an inverse relationship between the prevalence of hypertension and poor control, with BMI. Moreover, patients with lower BMI had greater left ventricular mass index, and greater evidence of extracellular fluid volume excess. Leaner patients had accelerated mortality in the first 2 years of follow-up, which he noted was not completely explained by blood pressure, left ventricular mass index, …