Association Between the Lactate‐to‐Albumin Ratio and ICU/In‐Hospital Mortality in Critically Ill Patients With Comorbid Type 2 Diabetes Mellitus : A Cohort Study Utilizing the MIMIC‐IV Database

Background Type 2 diabetes mellitus (T2DM) accounts for over 90% of diabetes cases worldwide, and its rising prevalence poses a substantial public health challenge. The lactate‐to‐albumin ratio (LAR) is a novel biomarker that reflects both metabolic stress and nutritional‐inflammatory status, and it has demonstrated independent prognostic value in various critical illnesses. However, its association with mortality in critically ill patients with T2DM remains unclear. This study aims to evaluate the predictive value of LAR for prognosis in this specific patient population through a retrospective analysis. Methods This retrospective observational cohort study utilized data from the Medical Information Mart for Intensive Care IV (MIMIC‐IV) v3.0 database, which includes complete medical records of patients admitted to the intensive care unit (ICU) of a U.S. medical center between 2008 and 2022. Subjects were categorized into three groups based on LAR tertiles. The study assessed ICU mortality and in‐hospital mortality as primary outcomes; 30‐day, 90‐day, and 365‐day mortality after ICU admission served as secondary outcomes. Machine learning identified key variables related to LAR and outcomes. The association between LAR and primary outcomes was analyzed using multivariate logistic regression and restricted cubic spline (RCS) regression. Cumulative mortality was analyzed using Kaplan–Meier curves. Threshold effects were evaluated using generalized additive models to enhance clinical applicability. Sensitivity and subgroup analyses were used to validate the robustness of the results and the interactions within subgroups. Result The study included 5463 critically ill T2DM patients. Using Boruta and SHapley Additive exPlanations (SHAP) algorithms, 14 key variables were identified. RCS analysis revealed a nonlinear relationship between LAR and in‐hospital mortality ( p for nonlinearity = 0.001). Threshold effect analysis identified a critical LAR threshold of 2.10. Kaplan–Meier survival curves showed that higher LAR values were correlated with increased mortality ( p < 0.001). Subgroup analyses revealed significant interactions in gender subgroups for ICU mortality ( p for interaction = 0.043) and in hyperlipidemia (HLD) subgroups for in‐hospital mortality ( p for interaction = 0.049). Sensitivity analyses confirmed robust associations between LAR and ICU mortality (OR 1.32, 95% CI: 1.20–1.45, p < 0.001) and in‐hospital mortality (OR 1.37, 95% CI: 1.26–1.50, p < 0.001). Conclusion This study identified a significant correlation between elevated LAR and adverse ICU outcomes in critically ill patients with T2DM.