In-hospital mortality of habitual cigarette smokers after acute myocardial infarction; the "smoker's paradox" in a countrywide study.

AIMS

Habitual cigarette smokers, paradoxically, present improved short-term prognosis after acute myocardial infarction, a phenomenon often termed "smoker's paradox". We sought to examine cigarette smokers' post-infarction survival advantage in a countrywide survey of unselected, consecutive patients presenting with acute myocardial infarction.

METHODS AND RESULTS

The study population was derived from the registry of the Hellenic study of acute myocardial infarction, which recruited 7433 consecutive patients with acute myocardial infarction from 76, out of a total of 86, hospitals countrywide. Cigarette smokers presented with lower unadjusted mortality rates (7.4% vs 14.5%, P<0.001), were younger, predominantly of male gender and were less likely to suffer from diabetes mellitus and arterial hypertension. When all univariate predictors of poor outcome were included as covariates in multivariate analysis, smoking status was not significantly associated with inhospital mortality (relative risk=1.12, 95% CI=0.86-1.44, P=0.399). The beneficial effect of thrombolytic therapy was independent of the smoking status in both univariate and multivariate analysis.

CONCLUSION

Unadjusted mortality rates are significantly lower in smokers, but age accounted for much of their seemingly improved outcome. When a number of additional clinical variables were taken into consideration, no significant influence of habitual smoking on early outcome following acute myocardial infarction was observed.