Red cell distribution width-to-albumin ratio predicts mortality in critically ill patients with gastrointestinal bleeding: A retrospective cohort study with external validation.

ObjectiveThe red cell distribution width-to-albumin ratio reflects systemic inflammatory burden and nutritional status. However, its prognostic value in critically ill patients with gastrointestinal bleeding has not been well established. This study assessed the association between the red cell distribution width-to-albumin ratio and mortality and developed a multivariable model for early risk stratification and mortality estimation.MethodsThis retrospective cohort study included adult intensive care unit patients with a primary diagnosis of gastrointestinal bleeding from the Medical Information Mart Intensive Care IV database, with external validation performed using the electronic intensive care unit Collaborative Research Database. Covariates for Cox proportional hazards models examining 28-day and 90-day mortality were selected using the least absolute shrinkage and selection operator in combination with clinical judgment. Kaplan-Meier survival analyses, receiver operating characteristic curves, and restricted cubic spline modeling were performed. Predictors identified by the Boruta algorithm were incorporated into a nomogram for early mortality estimation.ResultsA total of 1620 patients were included, with a 28-day mortality of 18.6%. Non-survivors exhibited substantially higher red cell distribution width-to-albumin ratio values. After full adjustment, the red cell distribution width-to-albumin ratio remained significantly associated with 28-day mortality (hazard ratio 1.12, 95% confidence interval 1.07-1.18) and 90-day mortality (hazard ratio 1.14, 95% confidence interval 1.09-1.20; both