The creatinine-to-albumin ratio as a prognostic indicator in critically ill patients with cirrhosis: A cohort study

The prognostic significance of the creatinine-to-albumin ratio (CAR) in various diseases is well-established; however, its utility in forecasting survival in patients with cirrhosis remains to be determined. This study aims to examine the association between CAR and mortality in cirrhotic patients. This retrospective cohort study evaluated the association between CAR and mortality in critically ill patients with cirrhosis. The primary outcome was 28-day all-cause mortality after intensive care unit (ICU) admission, and the secondary outcomes were 90-, 180-, and 365-day all-cause mortality after ICU admission. Cox regression, Kaplan–Meier survival analysis, receiver operating characteristic curve analysis, restricted cubic spline modeling, and subgroup analyses were performed to assess the prognostic value of CAR. The fully adjusted Cox model included demographic factors, selected vital signs and laboratory variables, cirrhosis-related complications, sepsis, and mechanical ventilation. External validation was performed in the eICU Collaborative Research Database cohort using the same CAR cutoff and analytical methods. This study included 1083 patients, with in-hospital and ICU mortality rates of 22.1% and 13.7%. Using X-tile software, the optimal CAR cutoff was 0.53, defining high-risk (CAR ≥ 0.53) and low-risk (CAR < 0.53) groups. Higher CAR was associated with increased mortality at 28, 90, 180, and 365 days (all P  < .05). Cox regression confirmed CAR as an independent predictor across all time points, and Kaplan–Meier curves showed consistently poorer survival in the high-risk group (all P  < .05). Receiver operating characteristic analysis indicated moderate discrimination for short- and long-term mortality, with area under the curve values exceeding creatinine and albumin. Restricted cubic spline modeling demonstrated an overall positive association between CAR and mortality risk, with evidence of nonlinearity for longer-term outcomes. Subgroup analyses showed consistent findings across strata, with no significant interactions. External validation in the eICU Collaborative Research Database cohort showed consistent associations between elevated CAR and increased 28-day mortality. CAR was independently associated with mortality and may serve as a simple adjunctive prognostic marker in critically ill patients with cirrhosis.