The prognostic value of hemoglobin-to-albumin ratio in critically ill patients with atrial fibrillation: A retrospective cohort study

Atrial fibrillation (AF) is common in critically ill patients and contributes to poor outcomes. Existing risk scores provide limited prognostic value for overall mortality. The hemoglobin-to-albumin ratio (HAR), reflecting hematologic and nutritional-inflammatory status, may serve as a novel prognostic biomarker in this setting. We performed a retrospective cohort study using the Medical Information Mart for Intensive Care IV database (version 3.1). Adult intensive care unit patients with AF were included, excluding those with multiple admissions, hospital stay <24 hours, or missing laboratory data. The primary outcome was 28-day all-cause mortality, and the secondary outcome was 360-day mortality. Patients were stratified by HAR quartiles. Kaplan-Meier analysis, Cox proportional hazards models, and restricted cubic splines were applied. Subgroup analyses assessed consistency across clinical strata. A total of 7801 patients were included (median age 75 years; 40.9% male). The 28- and 360-day mortality rates were 20.1% and 25.9%, respectively. Higher HAR was associated with increased mortality (log-rank P < .001). In fully adjusted Cox models, HAR independently predicted 28-day mortality (hazard ratio: 1.07, 95% confidence interval: 1.03-1.11) and 360-day mortality (hazard ratio: 1.07, 95% confidence interval: 1.04-1.11). Restricted cubic splines showed an approximately linear relationship. Subgroup analyses indicated stronger associations in older patients, those not receiving beta-blockers, and in amiodarone users at 360 days. HAR is an independent predictor of short- and long-term mortality in critically ill AF patients. As a simple and routinely available biomarker, HAR may enhance risk stratification beyond conventional clinical tools. Further prospective and multicenter studies are warranted to validate these findings.