Clinical value of blood–urea–nitrogen-to-albumin ratio in predicting in-hospital adverse outcomes among patients with STEMI

To investigate the predictive value of the blood–urea–nitrogen/albumin ratio (BAR) for in-hospital major adverse cardiovascular events (MACE) in patients with ST-segment elevation myocardial infarction (STEMI) and to develop a risk prediction tool based on a multivariable model. A retrospective cohort of 343 STEMI patients was enrolled and divided into MACE and non-MACE groups based on the occurrence of in-hospital MACE, defined as a composite of all-cause mortality, cardiogenic shock, malignant arrhythmia, and reinfarction. Differences in general characteristics and laboratory parameters were compared between groups. Univariate and multivariate logistic regression analyses identified independent predictors of in-hospital MACE, which were used to construct a nomogram model. Predictive performance was evaluated using Receiver Operating Characteristic (ROC) curves, and internal validation and calibration were evaluated using bootstrap resampling (1,000 iterations). Among 343 patients, 78 (22.7%) experienced in-hospital MACE. Compared with the non-MACE group, patients with MACE were older, had lower diastolic blood pressure, higher Killip class, lower left ventricular ejection fraction (LVEF), and higher BAR (all P < 0.05). In multivariable analysis, Killip class (OR 1.902; 95% CI 1.385–2.611; P < 0.001), LVEF (OR = 0.929, 95% CI 0.906–0.950; P < 0.001), and BAR (OR = 2.097, 95% CI 1.628–2.763; P < 0.001) were independent predictors of in-hospital MACE. BAR showed moderate discrimination for MACE (AUC = 0.695, 95% CI 0.628–0.763; P < 0.001), with an optimal cutoff of 1.716 (sensitivity 79.5%, specificity 49.4%). The nomogram incorporating Killip class, LVEF, and BAR demonstrated good performance, with an apparent AUC of 0.819 and an optimism-corrected AUC of 0.813; calibration was satisfactory. Elevated admission BAR is associated with a higher risk of in-hospital MACE in STEMI patients. A nomogram integrating Killip class, LVEF, and BAR may facilitate early in-hospital risk stratification as an adjunct to routine clinical assessment. Trial registration This study was a retrospective observational analysis and did not involve any healthcare intervention in human participants.