Role of cigarette smoking and gender in acute coronary syndrome events

Abstract

Cigarette smoking has been associated with lower mortality after an acute coronary event. We hypothesized that the improved survival in smokers is related to demographic differences and sought to further evaluate the gender disparities in smokers after an acute coronary event. A prospective cohort of 3,588 patients hospitalized at a single center from 1999 to 2006 was identified. Smoking status, in-hospital and 6-month follow-up death, and cardiovascular events (i.e., myocardial infarction, stroke, cardiac-related rehospitalization, and unscheduled revascularization) were assessed. The prevalence of smoking in men increased over time. The smokers were younger at presentation with fewer co-morbidities than nonsmokers. Male smokers had lower mortality (3.2% vs 5.4%, p = 0.04) and fewer cardiovascular events (33.1% vs 42.4%, p = 0.003) at 6 months than nonsmokers. However, after adjusting for age and co-morbidities, smoking was not an independent predictor of events (odds ratio 0.88, 95% confidence interval 0.67 to 1.17). Female smokers had mortality (5.6% vs 8.4%, p = 0.15) and cardiovascular events (54.5% vs 49.7%, p = 0.28) at 6 months similar to that of nonsmokers, with a nonsignificant trend toward increased risk after adjustment (odds ratio 1.31, 95% confidence interval 0.90 to 1.93). Among smokers, female gender remained a significant risk factor for cardiovascular events at 6 months (odds ratio 2.35, 95% confidence interval 1.58 to 3.50), even after adjustment for age and co-morbidities. In conclusion, smokers experienced acute coronary event events earlier than did nonsmokers. Younger age and fewer co-morbidities likely account for most observed survival benefit in smokers, although female smokers are more likely to experience cardiovascular complications by 6 months than male smokers.