Background: There are few and conflicting data regarding the prognostic role of continued smoking in very young survivors of acute myocardial infraction (AMI) after the event.
Design: We conducted a prospective study to evaluate the impact of smoking habits on long-term outcome in individuals who sustained AMI at the age of <or=35 years.
Methods: We recruited 147 consecutive patients who had survived their first AMI at the age of <or=35 years. Patients were followed up for up to 10 years. Clinical end points were: readmission for acute coronary syndrome, cardiac death or coronary revascularization because of clinical deterioration.
Results: The most prevalent risk factor at presentation was smoking (94.8%). Follow-up data were obtained by 135 patients (32+/-3 years old, 115 men). During follow-up 75 (55.6%) patients reported continuation of smoking. Forty-four (32.6%) patients presented cardiac events (three cardiac deaths, 30 acute coronary syndromes, and 11 revascularizations). Multivariable data analysis showed that persistence of smoking (relative risk=2.35, 95% confidence interval 1.5-5.25, P=0.03) and ejection fraction at presentation (relative risk=0.95, 95% confidence interval 0.91-0.98, P=0.008) were the only significant predictors of cardiac events after adjusting for various confounding factors. In addition, continuation of smoking was the most significant predictor of cardiac events during follow-up in our sample (i.e. had the lowest log-likelihood ratio as compared with ejection fraction or other covariates).
Conclusion: Persistence of smoking is the most powerful predictor for the recurrence of cardiac events in patients with premature AMI.