Smoker's paradox in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention

Background-prior studies have found that smokers undergoing thrombolytic therapy for st-segment elevation myocardial infarction have lower in-hospital mortality than nonsmokers,a phenomenon called the smoker's paradox. evidence,however,has been conflicting regarding whether this paradoxical association persists in the era of primary percutaneous coronary intervention. methods and results-we used the 2003-2012 national inpatient sample databases to identify all patients aged ≥18 years who underwent primary percutaneous coronary intervention for st-segment elevation myocardial infarction. multivariable logistic regression was used to compare in-hospital mortality between smokers (current and former) and nonsmokers. of the 985 174 patients with st-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention,438 954 (44.6%) were smokers. smokers were younger,were more often men,and were less likely to have traditional vascular risk factors than nonsmokers. smokers had lower observed in-hospital mortality compared with nonsmokers (2.0% versus 5.9%; unadjusted odds ratio 0.32,95% ci 0.31-0.33,p<0.001). although the association between smoking and lower in-hospital mortality was partly attenuated after baseline risk adjustment,a significant residual association remained (adjusted odds ratio 0.60,95% ci 0.58-0.62,p<0.001). this association largely persisted in age-stratified analyses. smoking status was also associated with shorter average length of stay (3.5 versus 4.5 days,p<0.001) and lower incidence of postprocedure hemorrhage (4.2% versus 6.1%; adjusted odds ratio 0.81,95% ci 0.80-0.83,p<0.001) and in-hospital cardiac arrest (1.3% versus 2.1%; adjusted or 0.78,95% ci 0.76-0.81,p<0.001). conclusions-in this nationwide cohort of patients undergoing primary percutaneous coronary intervention for st-segment elevation myocardial infarction,we observed significantly lower risk-adjusted in-hospital mortality in smokers,suggesting that the smoker's paradox also applies to st-segment elevation myocardial infarction patients undergoing primary percutaneous coronary intervention. © 2016 the authors.