Monitoring Volume Status Using Bioelectrical Impedance Analysis in Chronic Hemodialysis Patients

Fluid overload can be an independent risk factor of cardiovascular events and all-cause death in end-stage renal disease (ESRD) patients on chronic hemodialysis. We performed a retrospective study to investigate whether intermittent control of fluid status decreases the rate of these complications using bioelectrical impedance analysis (BIA). In ESRD patients on chronic hemodialysis, we identified the ratio of extracellular water to total body water (ECW/TBW) every 6 months using InBody S10 (Biospace, Seoul, Korea), which was measured within 30 minutes after dialysis initiation on the first dialysis day of the week. The uncontrolled group included 57 (40.1%) patients with all ECW/TBW measurements ≥0.40; in contrast, the controlled group included 85 (59.9%) with any measured ECW/TBW <0.40. Included patients were followed for 29 (12-42) months. The risk of cardiovascular events was higher in the uncontrolled group (hazard ratio [HR], 2.4; 95% confidence interval [CI], 1.2-5.1; p < 0.05) than it was in the controlled group; however, this difference disappeared after adjusting for age, sex, and Charlson comorbidity index (not significant). On the other hand, the patients in the uncontrolled group had a higher risk of all-cause death than did those in the controlled group, independent of age, sex, and Charlson comorbidity index (HR, 4.7; 95% CI, 1.4-16.1; p < 0.05). In conclusion, monitoring volume status using BIA may help to predict all-cause death in chronic hemodialysis patients. Further controlled studies are needed to confirm that strict volume control could reduce the rates of cardiovascular events and mortality in this population.