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

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.