Association Between Changes in Bioelectrical Impedance Analysis (BIA) Parameter and the Clinical Outcomes in Patients With Acute Heart Failure

Background: Volume overload is associated not only with clinical manifestations but also with poor outcomes of heart failure (HF). However, there is an unmet need for effective methods for serial monitoring of volume status during HF hospitalization. The aim of this study was to evaluate the prognostic implication of serial measurement of bioelectrical impedance analysis (BIA) in patients hospitalized with acute HF. Methods: This study is a retrospective observational study and screened 310 patients hospitalized due to acute decompensated HF between November 2021 and September 2022. Among them, 116 patients with acute HF who underwent BIA at the time of admission and at discharge were evaluated. We investigated the correlation between change of BIA parameters and the primary composite outcome (in-hospital mortality or rehospitalization for worsening HF within one month). Results: The median (interquartile range) age was 77 years (67-82 years). The mean left ventricular ejection fraction was 40.7 & PLUSMN; 14.6% and 55.8% of HF patients have HF with reduced ejection fraction. The body water composition (intracellular water [ICW], extracellular water [ECW], and total body water [TBW]) showed a statistically significant correlation with body mass index and LV chamber sizes. Furthermore, the ratio of ECW to TBW (ECW/TBW), as an edema index showed a significant correlation with natriuretic peptide levels. Notably, the change of the edema index during hospitalization (AECW/TBW) showed a significant correlation with the primary outcome. The area under the curve of AECW/TBW for predicting primary outcome was 0.71 (95% confidence interval [CI], 0.61-0.79; P = 0.006). When patients were divided into two groups based on the median value of AECW/TBW, the group of high and positive AECW/TBW (+0.3% to +5.1%) had a significantly higher risk of the primary outcome (23.2% vs. 8.3%, adjusted odds ratio, 4.8; 95% CI, 1.2-19.3; P = 0.029) than those with a low and negative AECW/TBW (-5.3% to +0.2%). Conclusion: BIA is a noninvasive and effective method to evaluate the volume status during the hospitalization of HF patients. The high and positive value of AECW/TBW during hospitalization was associated with poor outcomes in patients with HF.