Association of serum creatinine-to-albumin ratio with all-cause mortality in patients with sepsis-associated ARDS in the intensive care unit: a retrospective analysis based on the MIMIC-IV database

Sepsis complicated by acute respiratory distress syndrome (ARDS) is associated with substantially increased mortality. This analysis aimed to investigate the association of serum creatinine-to-albumin ratio (CAR) with poor prognosis in this population. Based on the Medical Information Mart for Intensive Care IV, this study used Kaplan-Meier (KM) survival curves to compare mortality outcomes among patients with sepsis-associated ARDS (SA-ARDS) across CAR subgroups. Multicollinearity among model variables was assessed. Both the Cox proportional hazards model (PHM) and the restricted cubic spline (RCS) regression were used to investigate the association of CAR with all-cause mortality (ACM) in patients with SA-ARDS. Subgroup analyses were performed to assess the robustness of the results. Among the 2,093 patients included, the 30-day ACM was 32.25%. KM survival curves showed that the Q4 group had a significantly higher 30-day ACM than the other groups (log-rank P < 0.001). In the fully adjusted model, Cox PHM showed that each one-unit increase in CAR was associated with a 50.7% higher risk of death (hazard ratio [HR] = 1.507, 95% confidence interval [CI]: 1.361–1.67, P < 0.001). When CAR was analyzed as a categorical variable, the Q4 group (high CAR) had a 45.1% higher risk of death than the Q1 group (low CAR) (HR = 1.451, 95% CI: 1.108-1.90, P = 0.007). RCS analysis indicated a nonlinear association between CAR and ACM. Subgroup analyses and interaction tests supported the robustness of the results. A significant association was found between CAR and ACM in patients with SA-ARDS. CAR may serve as a potential prognostic indicator for ACM in such patients and may aid early risk stratification. Not applicable.