Assessment of volume status with bioimpendance prior to hemodialysis and its importance for predicting survival in hemodialysis patients.

Abstract

Optimal fluid management is a physician's everyday challenge in patients on maintenance hemodialysis (HD). Bioimpedance spectroscopy (BIS) is a non-invasive method to estimate body composition, including estimates of fluid overload (FO). Our study aimed to analyze the association between FO and the mortality rate in HD patients. We performed a retrospective single-center cohort study in 92 HD patients. The body composition was measured before HD using the portable whole-body BIS device Body Composition Monitor (BCM). We have analyzed the mortality rates of HD patients in two FO groups, a standard definition FO group (> 1.1 L), and a severe FO group (> 2.5 L) and compared them to mortality rates of patients without FO or without severe FO, respectively. The mean age of patients was 64.3 ± 13.0 years, mean dialysis vintage 64 months, 60.9% were men. 68 (73.9%) patients had FO of > 1.1 L and 30 (32.6%) had FO of > 2.5 L. During the follow-up period of 1,020 ± 417 days, 29 (31.5%) patients died. Kaplan-Meier survival analysis showed that patients with FO > 2.5 L had worse survival (p = 0.039). In a Cox regression model, which included FO > 2.5 L, age, dialysis vintage, hemoglobin, C-reactive protein, and albumin, only FO > 2.5 L and advanced age turned out to be predictors of death (p = 0.044 and p = 0.001, respectively). HD patients with FO > 2.5 L before HD have poorer survival than patients with normohydration or lower overhydration.