Bioimpedance Spectroscopy in Acute Decompensated Heart Failure: Insights on Fluid Status and Outcomes

BackgroundAcute decompensated heart failure (ADHF) is a leading cause of hospitalization, driven by fluid overload and associated with poor outcomes. Bioimpedance spectroscopy (BIS) provides a non-invasive method to assess fluid status, but its utility in predicting clinical outcomes, especially in chronic kidney disease (CKD) and heart failure with preserved ejection fraction (HFpEF), remains unclear. MethodsThis prospective study enrolled 157 patients hospitalized for ADHF. BIS was performed at admission and discharge to measure overhydration (OH) and the OH-to-extracellular water (OH/ECW) ratio. Patients were stratified into subgroups by CKD and heart failure with reduced ejection fraction (HFrEF). Outcomes included major adverse cardiovascular events (MACE) and heart failure hospitalization (HHF). Cox proportional hazards models, adjusted for age, sex, NT-proBNP, and ejection fraction, were used to evaluate the prognostic value of BIS parameters. ResultsAmong the 157 patients, 72 (45.9%) had CKD, and 111 (70.7%) had HFrEF. CKD patients exhibited significantly higher OH and OH/ECW ratios at admission but showed no association with MACE or HHF. Greater reductions in OH/ECW were observed in HFrEF patients compared to non-HFrEF (P = 0.036), indicating better response to diuresis. However, these changes did not translate into improved clinical outcomes. Across all subgroups, OH, OH/ECW, and changes in these parameters were not significant predictors of MACE or HHF during the 10.7 {+/-} 7.1-month follow-up. ConclusionsBIS effectively monitors fluid status in ADHF patients, particularly in HFrEF. However, its prognostic utility in predicting outcomes in CKD and HFpEF subgroups is limited, warranting further investigation.