Prognostic value of overhydration and bioelectrical impedance vector on short- and long-term outcomes in hospitalized patients with cancer

Water, an essential component of body composition, appears to be a significant predictor of adverse outcomes in clinical populations, despite being frequently underexplored. Bioelectrical impedance analysis (BIA) and vector analysis (BIVA) are easy and cost-effective bedside tools for estimating body composition, particularly water content. Therefore, our study aimed to assess the impact of hydration and fluid status using both BIA and BIVA on outcomes in hospitalized patients with cancer. A prospective cohort study involving hospitalized individuals with cancer was conducted. Total body water (TBW) was estimated using BIA. Extracellular-water/TBW (ECW/TBW) and ECW/intracellular-water (ECW/ICW) ratios were calculated. BIVA ellipses vectors were constructed to enhance our analysis of hydration status. Participants were followed during their hospital stay and up to six months after discharge to assess outcomes, including in-hospital mortality, 6-month non-elective rehospitalization, and 6-month mortality. TBW, ECW/TBW, ECW/ICW ratios, and BIVA plots were not associated with non-elective rehospitalization during the follow-up period. However, TBW and an elevated ECW/ICW ratio were independent predictors of in-hospital mortality [hazard ratio (HR): 1.07 (1.01; 1.13) p = 0.020; HR: 4.23 (1.69; 10.58) p = 0.002]. Elevated ratios ECW/TBW and ECW/ICW were independent predictors of 6-month mortality [HR: 1.87 (1.10; 3.21) p = 0.022; HR: 2.49 (1.37; 4.51) p = 0.003]. BIVA vectors for in-hospital and 6-month mortality shifted significantly to the right, leading to cachexia and overhydration quadrants (p