Association of Red Blood Cell Distribution Width-to-Albumin Ratio with In-Hospital Mortality in Adult Patients with Diabetic Ketoacidosis

Background and Objectives: Diabetic ketoacidosis (DKA) is a life-threatening acute metabolic complication of diabetes. Early identification of patients at high risk of mortality is crucial for optimal management. This study evaluated the prognostic association of the red blood cell distribution width-to-albumin ratio (RAR) and other laboratory biomarkers with in-hospital mortality and intensive care unit (ICU) admission in adult patients with DKA. Materials and Methods: In this retrospective single-center study, 86 adults hospitalized with DKA after emergency department admission between January 2021 and January 2026 were included. Demographic, laboratory, and clinical data were analyzed. The discriminatory performance of RAR, blood urea nitrogen-to-albumin ratio (BAR), and Red blood cell distribution width (RDW) for in-hospital mortality was assessed using receiver operating characteristic (ROC) analysis. Associations with in-hospital mortality were examined using logistic regression. Results: In-hospital mortality was 11.6%, and 79.1% of patients required ICU admission. Non-survivors had significantly higher inflammatory and metabolic biomarkers and lower albumin and pH. RAR showed the numerically highest Area Under the Curve (AUC) among the evaluated indices (AUC: 0.826, 95% Confidence interval (CI): 0.691–0.962), compared with BAR (AUC: 0.803, 95% CI: 0.632–0.973) and RDW (AUC: 0.713, 95% CI: 0.547–0.879). In the exploratory multivariable analysis, age (OR: 1.06), lactate (OR: 1.31), pH (OR: 0.002), albumin (OR: 0.28), and RAR (OR: 1.98) were associated with in-hospital mortality. Conclusions: RAR was associated with in-hospital mortality in adults with DKA and had the numerically highest AUC among the evaluated indices. However, these findings are exploratory, do not establish superior discrimination over other biomarkers, and require validation in larger, independent cohorts.