The association between the MELD-XI score and 30-day mortality in ICU patients with sepsis: a retrospective cohort study.

Sepsis is a leading cause of mortality among ICU patients. Although APACHE IV and SOFA scores are widely employed for prognostic assessment, their complexity and dependence on extensive data may limit their effectiveness in early risk identification. The MELD-XI score, derived from serum total bilirubin and creatinine, offers a simple calculation method and has demonstrated strong prognostic value in liver disease, organ transplantation, and cardiovascular conditions. However, its prognostic utility in ICU patients with sepsis has not been systematically evaluated. In this study, we retrospectively analyzed 16,691 adult patients diagnosed with sepsis within 48 h of ICU admission using data from the eICU Collaborative Research Database. Through the application of a generalized additive model and a two-stage linear regression model, we identified for the first time a significant nonlinear association and a threshold effect between MELD-XI scores and 30-day all-cause mortality. The turning point was determined at a MELD-XI score of 25.74, with mortality risk increasing by 1.1% per unit below the threshold and by 5.5% per unit above it. Stratified subgroup analyses confirmed the consistency of this association across most clinical categories. These findings suggest that the MELD-XI score may serve as a simple, accessible, and complementary tool for early risk stratification and clinical decision-making in ICU patients with sepsis.