Malnutrition and fluid overload as independent predictors of mortality in dialysis patients: A multicenter cohort study in Colombia

Objective: To estimate and compare the impact of malnutrition and fluid overload on mortality among patients with chronic kidney disease (CKD) undergoing renal replacement therapy (RRT), considering their frequent coexistence and potential to exacerbate underlying comorbidities. Methods: We conducted a retrospective cohort study of patients on dialysis between January 2018 and January 2020 in six dialysis units across six Colombian cities. Multivariate analysis was conducted using multiple regression models, adjusting for clinically and statistically significant covariates. Survival at 12 months was compared between groups. Results: A total of 807 patients were included. Of these, 154 (19.1%) presented malnutrition and 369 (45.8%) fluid overload. In multivariate analysis, malnutrition was the strongest predictor of mortality, increasing the risk of death more than sixfold compared to baseline (HR = 7.4; 95% CI: 1.7–31; p = 0.006). Fluid overload was also significantly associated with higher mortality risk (HR = 1.7; 95% CI: 1.0–2.9; p = 0.05). Conclusions: Both malnutrition and fluid overload adversely affected survival in CKD patients undergoing RRT, with malnutrition emerging as the strongest independent risk factor for mortality.