Association between albumin-bilirubin score and all-cause mortality in patients with acute respiratory failure: a cohort study based on the MIMIC-IV database.

Background: The albumin-bilirubin (ALBI) score represents a novel indicator integrating liver function and nutritional status. Its prognostic value has been demonstrated in a variety of diseases, but its prognostic significance in individuals with acute respiratory failure (ARF) is still elusive. This research aimed to discern the association between ALBI score and short-term all-cause mortality (ACM) in individuals with ARF admitted to the intensive care unit (ICU). Methods: This was a retrospective cohort study. Data were acquired from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Totally, 6,285 individuals with ARF were included in this study. These individuals were classified into four groups as per the quartile of the ALBI score. The primary outcome was the 30-day ACM rate, and the secondary outcome was the 90-day ACM rate. Kaplan-Meier (KM) curves were used to compare survival rates among the cohorts. The association between ALBI score and ACM rates was explored using a multivariate Cox proportional hazards regression model and restricted cubic spline (RCS) analysis. The area under the receiver operating characteristic (ROC) curve (AUC) was calculated, and the incremental predictive value of ALBI was evaluated by the integrated discrimination improvement (IDI) and net reclassification improvement (NRI). Results: Among the 6,285 participants, the median age was 65.92 years, and 56.66% were male. KM analysis implied that a higher ALBI score was significantly associated with reduced 30- and 90-day survival rates (log-rank test P<0.001). Multivariate Cox regression analysis suggested that compared with the lowest quartile (Q1), individuals with the highest ALBI score (Q4) had a 44.6% elevated risk of 30-day ACM [hazard ratio (HR): 1.446; 95% confidence interval (CI): 1.208 to 1.731] and a 58.0% elevated risk of 90-day ACM (HR: 1.580; 95% CI: 1.347 to 1.853). RCS analysis further implied a linear positive association between ALBI score and the risk of ACM. Furthermore, incorporating ALBI score into the Sequential Organ Failure Assessment (SOFA) and Oxford Acute Severity of Illness Score (OASIS) scoring systems improved the model's predictive accuracy. Conclusions: In individuals with ARF in the ICU, a higher ALBI score at admission is independently associated with a significantly elevated risk of 30- and 90-day ACM. The ALBI score may serve as a useful adjunctive tool for risk stratification, but its clinical utility needs to be corroborated in prospective and external validation studies.