Relationship of the Endothelial Activation and Stress Index with 28-day mortality in urosepsis patients: a retrospective two-cohort investigation.

Background: The Endothelial Activation and Stress Index (EASIX) is a novel biomarker for assessing endothelial dysfunction. This study aimed to evaluate its prognostic value for 28-day mortality in patients with urosepsis. Materials and methods: We conducted a retrospective study of patients with urosepsis admitted to the ICU using data from the MIMIC-IV database and West China Hospital. Restricted cubic spline (RCS) regression, multivariable Cox regression, and Kaplan-Meier analysis were used to assess the association between EASIX and short-term mortality. Four machine learning feature selection methods (LASSO-COX, Boruta, random forest, and gradient boosting) were applied to identify key prognostic features and develop a predictive model, which was evaluated using ROC curve analysis and validated in an external cohort. Result: A total of 2,593 patients were included. The 28-day ICU and in-hospital mortality rates were 16.0 and 17.2%, respectively. Higher EASIX scores were significantly associated with increased mortality across quartiles (ICU mortality: 10.5% in Q1 to 30.4% in Q4, Conclusion: EASIX is independently associated with short-term mortality in patients with urosepsis and may serve as a valuable tool for risk stratification following further validation.