A retrospective cohort study of the association between smoking and mortality after acute ST-segment elevation myocardial infarction
Several studies have shown a ‘smoker's paradox’, where following an acute myocardial infarction, smokers have a paradoxically lower mortality than non-smokers. To date, no large study has investigated this paradox in unselected patients with acute ST-segment elevation myocardial infarction (STEMI) managed by primary percutaneous coronary intervention (PCI) alone.Objectives
We aimed to examine the association of smoking status and 1-year mortality in patients who had STEMI managed by primary PCI.Methods
This retrospective study included all patients admitted with acute STEMI undergoing primary PCI in a single UK centre from January 2009 to April 2012. The survival status for all patients post-STEMI was obtained. Differences in survival by smoking status were assessed using a Kaplan-Meier curve, and after adjustment for age, gender and additional cardiovascular risk factors using a Cox regression analysis.Results
The 1-year mortality for patients with STEMI was 149/1796 (8.3%). There were 846/1796 (47.1%) current smokers, 476/1796 (26.5%) ex-smokers and 417/1796 (23.2%) never smokers. Current smokers were approximately 10 years younger than ex-smokers and never smokers (p=0.001). A multivariate Cox proportional hazards model found no evidence of an association between mortality and smoking status after adjustment; p=0.23. Compared with never smokers, the HR (95% CI) for 1-year mortality for current smokers was 1.47 (0.90 to 2.39) and 1.08 (0.66 to 1.77) for ex-smokers.Conclusions
In this retrospective cohort study, we found no evidence of an association between mortality and smoking status in patients with acute STEMI treated with PCI, and thus no evidence of a ‘smoker's paradox’.