Use of Multifrequency Bioimpedance Analysis in Male Patients with Acute Kidney Injury Who Are Undergoing Continuous Veno-Venous Hemodiafiltration

INTRODUCTION Fluid overload is a well-known predictor of mortality in patients with acute kidney injury (AKI). Multifrequency bioimpedance analysis (MF-BIA) is a promising tool for quantifying volume status. However, few studies have analyzed the effect of MF-BIA-defined volume status on the mortality of critically ill patients with AKI. This retrospective medical research study aimed to investigate this issue. METHODS We retrospectively reviewed the medical records of patients with AKI who underwent continuous veno-venous hemodiafiltration (CVVHDF) from Jan. 2013 to Feb. 2014. Female patients were excluded to control for sex-based differences. Volume status was measured using MF-BIA (Inbody S20, Seoul, Korea) at the time of CVVHDF initiation, and volume parameters were adjusted with height squared (H2). Binary logistic regression analyses were performed to test independent factors for prediction of in-hospital mortality. RESULTS A total of 208 male patients were included in this study. The mean age was 65.19±12.90 years. During the mean ICU stay of 18.29±27.48 days, 40.4% of the patients died. The in-hospital mortality rate increased with increasing total body water (TBW)/H2 quartile. In the multivariable analyses, increased TBW/H2 (OR 1.312(1.009-1.705), p=0.043) and having lower serum albumin (OR 0.564(0.346-0.919, p=0.022) were independently associated with higher in-hospital mortality. When the intracellular water (ICW)/H2 or extracellular water (ECW)/H2 was adjusted instead of the TBW/H2, only excess ICW/H2 was independently associated with increased mortality (OR 1.561(1.012-2.408, p=0.044). CONCLUSIONS MF-BIA-defined excess TBW/H2 and ICW/H2 are independently associated with higher in-hospital mortality in male patients with AKI undergoing CVVHDF.