Higher Mortality in Smokers Following Percutaneous Coronary Intervention

Background: “Smoker's paradox” refers to the observation that smokers, compared to non-smokers, appear to have lower mortality following myocardial infarction (MI). In some studies, this unexpected survival benefit remains despite multivariate analysis. We sought to determine the prognosis of smokers in a contemporary Australian cohort following percutaneous coronary intervention (PCI). Methods and results: We compared the demographic and clinical features between smokers, ex-smokers and non-smokers in the Melbourne Interventional Group Registry. Of 15,463 patients identified, 23.6% were current smokers, 44.1% were ex-smokers and 32.4% were non-smokers. Compared to non-smokers, current smokers were younger than non-smokers (56.5 years vs. 67.6 years, p < 0.001) and more likely to be male (79.9% vs. 61.7%, p < 0.001). They were less likely to have previous history of MI, coronary revascularisation, heart failure, impaired renal function, cerebrovascular disease, or cardiac risk factors including hypertension and diabetes (all p < 0.001). Smokers were more likely to have their index PCI for acute coronary syndrome (80.8% vs. 63.0%, p < 0.001). Unadjusted analysis showed that current smokers had lower mortality. However, in multivariate analysis, smokers had the highest mortality, followed by ex-smokers then non-smokers Conclusions: Smoking status is associated with higher mortality following PCI. The purported survival benefits of the “smoker's paradox” likely reflect younger age and fewer co-morbidities.