Blood urea nitrogen-to-albumin ratio and in-hospital mortality in patients with ST-elevation myocardial infarction undergoing primary percutaneous coronary intervention.

In-hospital mortality remains an important concern in patients with ST-elevation myocardial infarction (STEMI), highlighting the need for simple and readily available markers for early risk stratification. This study investigated the prognostic value of the blood urea nitrogen-to-serum albumin ratio (BAR) for in-hospital mortality in patients with STEMI undergoing primary percutaneous coronary intervention (pPCI). This single-center retrospective cohort study included 388 consecutive patients who underwent pPCI in 2024. Admission BAR was calculated using blood urea nitrogen (mg/dL) and serum albumin (g/L). Its association with in-hospital mortality was evaluated using receiver operating characteristic analysis and exploratory multivariable logistic regression, with Firth-penalized regression and bootstrap validation performed as sensitivity analyses. In-hospital death occurred in 18 patients (4.6%). Patients who died had significantly higher BAR values than survivors (0.7 vs. 0.4, p < 0.001). BAR showed good discrimination for in-hospital mortality, with an area under the curve of 0.869 (p < 0.001); the bootstrap-corrected area under the curve was also 0.869. An exploratory cut-off of 0.475 yielded 83.3% sensitivity and 75.4% specificity. In the multivariable model, each 0.1-unit increase in BAR was associated with higher odds of in-hospital mortality (odds ratio 1.412, 95% confidence interval 1.161-1.718; p = 0.0006), with a similar estimate in the Firth-penalized analysis (odds ratio 1.346, 95% confidence interval 1.121-1.616; p = 0.0008). Admission BAR may represent a simple candidate marker for early mortality risk stratification in STEMI patients undergoing pPCI; however, its prognostic performance and clinical utility require validation in larger prospective multicenter cohorts.