Premature Acute Myocardial Infarction in Southern Libya: Prevalence, Sex-Specific Risk Profiles, and a Bedside Risk Score

Background: Background: Premature acute myocardial infarction (AMI) is an increasing cause of cardiovascular morbidity across the Middle East and North Africa (MENA), but data from Southern Libya remain limited. Objective: To determine the prevalence and risk-factor profile of premature AMI and develop a preliminary internally validated risk-stratification model. Methods: In this retrospective study, 361 consecutive patients admitted with AMI to Sabha Medical Centre between October 2024 and March 2026 were classified as premature AMI (men ≤55 years, women ≤65 years; n=175) or non-premature AMI (n=186). Traditional cardiovascular risk factors were extracted from standardised medical records. Independent predictors were identified using multivariable logistic regression adjusted for age. Random Forest analysis ranked predictor importance. A weighted risk model was internally validated using a 30% held-out test set. Results: Premature AMI accounted for 48.5% (175/361) of admissions. Patients had a mean age of 49.2±8.6 years, and 71.4% were male. Smoking independently predicted premature AMI (adjusted OR 1.62, 95% CI 1.06–2.47; P=0.027), whereas hypertension was inversely associated (adjusted OR 0.54, 95% CI 0.37–0.80; P=0.002). Smoking was substantially more prevalent in young males than females (68.0% vs 2.0%; P<0.001). Among premature females, diabetes (52.0% vs 30.4%; P=0.007) and hypertension (50.0% vs 33.6%; P=0.041) were more common than in males. Random Forest identified smoking, hypertension, and diabetes as the most influential predictors (AUC 0.712). The internally validated risk model showed moderate discrimination (AUC 0.682). Conclusion: Nearly half of AMI admissions occurred in younger adults. Smoking was the dominant predictor of premature AMI, particularly in men, whereas diabetes and hypertension were more prominent in women. These findings support targeted prevention strategies in Southern Libya. The proposed risk model requires external validation before clinical application.