Collapse of Fluid Balance and Association with Survival in Patients with Advanced Cancer Admitted to a Palliative Care Unit: Preliminary Findings.

Abstract

Background: Few studies have investigated water balance as a predictor of survival in cancer patients in the last days of life. Objective: To examine the association between extracellular water (ECW), intracellular water (ICW), ratio of ECW to ICW (ECW/ICW), and survival in nonedematous and edematous patients with advanced cancer admitted to a palliative care unit. Design: A prospective observational study. Setting/Subjects: Patients with advanced cancer admitted to a palliative care unit. Measurements: Upon enrollment, bioelectrical impedance analysis was used to assess ECW, ICW, and body composition. We conducted time-to-event analyses using the Kaplan-Meier method, log-rank test, and univariate and multivariate Cox regression analyses. Results: A total of 190 of 204 patients who participated in this study had ICW and ECW measures available for analysis. The median survival was 10 days (95% confidence interval [CI] 9-12) days. The median ECW, ICW, and ECW/ICW were 18.9 L, 19.1 L, and 1.0 for 72 nonedematous patients, and 21.9 L, 20.1 L, and 1.1 for 118 edematous patients, respectively. In univariate Cox regression analysis, ICW ≤20 L was associated with a shorter survival in the nonedematous patients (hazard ratio [HR] 1.92, 95% CI 1.10-3.34, p = 0.02) and a longer survival in the edematous patients (HR 0.61, 95% CI 0.41-0.90, p = 0.01). In multivariable analysis, ICW (≤20 L vs. >20 L) remained an independent prognostic factor in edematous patients (HR 0.64, 95% CI 0.43-0.95, p = 0.03). Conclusions: Greater ICW was an independent predictor of poorer survival in cancer patients with edema in the last days of life.