Usefulness of Blood-Urea-Nitrogen to Serum Albumin Ratio for In-hospital Mortality Predictions in Atrial Fibrillation Patients Admitted to the Intensive Care Unit: A Retrospective Analysis From MIMIC-IV Database.

Background: Despite prior research showing that elevated BAR levels were linked to poor prognoses in several cardiovascular disease conditions, the predictive role of the blood-urea-nitrogen to serum albumin ratio (BAR) in atrial fibrillation (AF) patients admitted to the intensive care unit (ICU) remains largely unknown.

Methods: Patients diagnosed with AF were gathered from the Medical Information Mart for Intensive Care-IV (MIMIC-IV) database, and the X-tile software was used to determine the best cut-off values for BAR. The Kaplan-Meier curves and receiver operating characteristics (ROC) analyses were used to evaluate the prognostic value of the BAR. The identified prognostic indicators were used to build a nomogram model.

Results: Finally, 13,451 AF patients were included in this study. The best BAR cut-off value was 8.9. In-hospital survival was substantially higher in the low-BAR group (BAR ≤8.9) than in the high-BAR group (BAR >8.9) (HR: 3.15, 95% CI: 2.89-3.44; p < 0.001). A nomogram model was developed using the findings of multivariable logistic regression, considering variables such as age, heart rate, albumin, white blood cell count, simplified acute physiology score II (SAPS II) score, sequential organ failure assessment (SOFA) score, mechanical ventilation, and the BAR. When forecasting the probability of death for AF patients admitted to the ICU, the nomogram showed good performance and practical application. Calibration curves evaluated the accuracy of the model, decision curve analysis evaluated the clinical use of the model, and the area under the receiver operating characteristic (AUROC) curve evaluated the discriminative capabilities of the model.

Conclusion: Among critically ill AF patients, the BAR, a readily available clinical measure, shows outstanding predictive ability in predicting in-hospital mortality. Additionally, in-hospital mortality could be predicted with high accuracy using a nomogram that included the BAR.