Blood urea nitrogen to albumin ratio and mortality in critically ill patients with cardiogenic shock

Abstract

Purpose Given the high mortality associated with cardiogenic shock (CS), this study aimed to evaluate the association between the blood urea nitrogen-to-albumin ratio (BAR) and mortality in critically ill patients with CS. Patients and methods The data of this retrospective study were extracted from the Medical Information Mart for Intensive CARE-IV (MIMIC-IV v2.2) database. Patients who were diagnosed with CS were included as the study population. The primary outcome was one-year mortality, and secondary outcomes included in-hospital mortality and ICU mortality. Cox regression models were used to estimate the association between BAR and mortality.The prognostic value of BAR was assessed using the time-dependent area under the curve (AUC), net reclassification improvement (NRI), and integrated discrimination improvement (IDI). Results A total of 1,177 patients were enrolled in the study. After adjustment for covariates, BAR was associated with one-year mortality (HR: 1.02 [1.01–1.03], P  < 0.001 per 1-unit increase). Compared with the low-BAR group, the medium- and high-BAR groups showed higher risks of one-year mortality (medium group: HR 1.30 [1.02–1.66], P  = 0.034; high group: HR 1.75 [1.32–2.33], P  < 0.001). Similar associations were observed for in-hospital mortality (per 1-unit increase: HR 1.02 [1.01–1.04], P  < 0.001; high vs. low group: HR 1.51 [1.08–2.13], P  = 0.017) and ICU mortality (per 1-unit increase: HR 1.02 [1.01–1.04], P  < 0.001; high vs. low group: HR 1.67 [1.17–2.40], P  = 0.005). E‑value analysis suggested robustness to unmeasured confounding. BAR demonstrated favorable discriminative ability, with a time‑dependent AUC of 0.612 and a Harrell’s C‑index of 0.607. When combined with existing prognostic indicators, BAR significantly improved prognostic accuracy. Conclusion In this study, higher BAR levels were associated with increased mortality in CS patients. BAR provided incremental prognostic value when combined with existing indicators.