Creatinine-to-albumin ratio and all-cause mortality in patients with upper gastrointestinal bleeding: a retrospective study

This research aimed to assess the relationship between creatinine-to-albumin ratio (CAR) and clinical outcomes among individuals with upper gastrointestinal bleeding (UGIB), with a particular focus on the association between CAR and 30-day and 90-day all-cause mortality (ACM). Patient data were obtained from the Medical Information Mart for Intensive Care IV version 3.1 (MIMIC-IV 3.1) and the intensive care unit of the Second Hospital of Hebei Medical University (HMUSH). The included individuals were stratified into four groups according to CAR quartiles. The 30-day ACM served as the primary outcome, and the 90-day ACM as the secondary outcome. Clinical outcomes across groups were compared by Kaplan–Meier curves. Cox proportional hazards (PH) regression and restricted cubic spline (RCS) models were applied to examine the association between CAR and mortality outcomes. Moreover, subgroup analyses were carried out. In total, 1,685 individuals from the MIMIC-IV cohort and 408 individuals from the HMUSH cohort were enrolled. Kaplan–Meier curves demonstrated that higher CAR values were related to increased risks of 30-day and 90-day ACM (log-rank < 0.05). Cox PH regression indicated that those in the highest CAR quartile had 211% and 205% elevated risks of 30-day and 90-day ACM, respectively, in the MIMIC-IV cohort, and 241% and 182% higher risks, respectively, in the HMUSH cohort. Subgroup analysis demonstrated a significant interaction with concurrent cirrhosis. Elevated CAR values were significantly related to increased risks of 30-day and 90-day ACM among individuals with UGIB. These findings provide further insight into the relationship between serum indicators and prognosis among UGIB patients.