Clinical Profile and Outcomes of ST-Elevation Myocardial Infarction in Patients Under 45 Years

Background: ST-segment elevation myocardial infarction (STEMI) remains a leading cause of global mortality. Although overall incidence is declining, this trend is less evident among younger individuals, emphasizing the need to better understand modifiable risk factors and clinical outcomes in this population. Objective: To analyze the clinical profile and outcomes of young patients with STEMI undergoing primary percutaneous coronary intervention (pPCI) in a contemporary cohort. Methodology: This prospective cohort study included patients aged ≥18 years with confirmed STEMI treated with pPCI at a tertiary university hospital from March 2011 to January 2025. Patients were stratified into two groups: young (≤45 years) and older (>45 years). The primary outcome was in-hospital mortality. A two-sided significance level of p<0.05 was adopted. Results: A total of 2,050 patients were included; 191 (9.3%) were ≤45 years old (mean age: 39.9 years). Younger patients showed significantly lower in-hospital mortality (4.2% vs. 12.1%; p=0.001), shorter median length of stay (5 vs. 6 days; p=0.001), and lower incidence of long-term major adverse cardiovascular and cerebrovascular events (15.2% vs. 24.7%; p=0.003). They had higher prevalence of active smoking (57.1% vs. 40.6%; p<0.001), illicit drug use (18.3% vs. 10.0%; p<0.001), HIV infection (4.7% vs. 2.2%; p=0.003), and family history of coronary artery disease (24.2% vs. 12.4%; p<0.001). Conclusion: Young STEMI patients presented with fewer comorbidities and lower in-hospital mortality, but a higher prevalence of behavioral risk factors. These findings highlight the need for targeted preventive strategies and early detection to improve long-term outcomes.