Association between Active Smoking and ST-Elevation Myocardial Infarction among Patients Presenting With Acute Coronary Syndrome: A Comparative Cross-Sectional Study

Abstract

Objectives: To determine the association between active smoking and ST-elevation myocardial infarction (STEMI) among patients presenting with acute coronary syndrome (ACS) in a tertiary care hospital setting. Methodology: This comparative cross-sectional study was conducted in the Department of Cardiology, Jinnah Hospital Lahore, Pakistan, from April to October 2020. A total of 240 adult patients presenting with ACS were enrolled, including 120 active smokers and 120 non-smokers. Demographic characteristics, cardiovascular risk factors, smoking status, and ACS subtype were recorded using a structured proforma. ACS was classified into STEMI, NSTEMI, and unstable angina according to the Fourth Universal Definition of Myocardial Infarction. Results: The mean age of smokers and non-smokers was 44.23 ± 9.54 years and 42.72 ± 10.68 years, respectively. Male patients constituted 76.6% of smokers and 70.0% of non-smokers. STEMI was the most frequent ACS subtype and was observed in 70.8% of smokers compared with 65.0% of non-smokers. Smokers also demonstrated significantly lower BMI compared to non-smokers (20.3 ± 1.9 kg/m² vs. 23.1 ± 2.1 kg/m²; p < 0.001). Multivariable logistic regression analysis demonstrated that active smoking was independently associated with higher odds of STEMI presentation (adjusted OR = 1.85; 95% CI: 1.13–3.02; p < 0.05). Other variables including age, gender, diabetes mellitus, dyslipidemia, and BMI did not show statistically significant associations with STEMI. Conclusion: Active smoking was significantly associated with STEMI presentation among patients with ACS. These findings reinforce the role of smoking as an important and preventable cardiovascular risk factor. Strengthening smoking cessation programs, public awareness campaigns, and preventive cardiovascular strategies may help reduce the burden of STEMI and adverse cardiovascular outcomes in high-risk populations.