Prognostic Value of FIB-4 Index and Non-Alcoholic Fatty Liver Disease in Myocardial Infarction With Non-Obstructive Coronary Arteries: A Prospective Cohort Study

Myocardial infarction with non-obstructive coronary arteries (MINOCA) represents 5% to 10% of acute myocardial infarction cases. The Fibrosis-4 (FIB-4) index and non-alcoholic fatty liver disease (NAFLD) are emerging markers of systemic inflammation and metabolic dysfunction, yet their prognostic role in MINOCA remains unexplored. This prospective cohort study included 472 consecutive MINOCA patients from a tertiary cardiac center between September 2022 and October 2025. Patients were stratified by FIB-4 index (high ≥1.3, low <1.3). NAFLD was diagnosed using hepatic steatosis index. The primary endpoint was major adverse cardiovascular events (MACE): cardiovascular death, recurrent myocardial infarction, urgent revascularization, or hospitalization for heart failure or arrhythmia during 36-month follow-up. High FIB-4 index was independently associated with increased MACE risk (hazard ratio [HR]: 2.34, 95% confidence interval [CI]: 1.45-3.78, <i>P</i> < .001). NAFLD presence further augmented this risk (HR: 1.89, 95% CI: 1.23-2.91, <i>P</i> = .004). Patients with both high FIB-4 and NAFLD demonstrated worst outcomes (HR: 3.12, 95% CI: 1.87-5.21, <i>P</i> < .001). FIB-4 showed good discriminative ability for MACE prediction (AUC: 0.712, 95% CI: 0.665-0.759). FIB-4 index and NAFLD are independent predictors of adverse outcomes in MINOCA patients, offering simple, cost-effective tools for risk stratification.