Meta-Analysis Comparing Outcomes of Smokers Versus Nonsmokers With Acute Coronary Syndrome Underwent Percutaneous Coronary Intervention

Several studies have found improved mortality in smokers after acute coronary syndrome (ACS) especially in the thrombolytic era. We aimed to assess the association of smoking status with mortality and cardiovascular outcomes in patients with ACS treated with percutaneous coronary intervention (PCI). We searched PubMed, EMBASE, CINAHL, and Cochrane CENTRAL for randomized controlled trials since inception through February 15, 2018 and used random effects model for analysis. The outcomes analyzed were all-cause mortality, major adverse cardiac events (MACE), myocardial infarction, and target vessel revascularization at 1 month and 1 year. We included 17 randomized and nonrandomized studies with a total of 55,491 patients with 21,989 smokers' and 33,502 nonsmokers. In ACS patients treated with PCI, smokers were found to have lower mortality than nonsmokers at 30-day ([2.3% vs 3.3%; Odds ratio; 0.54; 95% confidence interval: 0.39 to 0.76; p <0.001, I2 = 74%] and 1-year [2.3% vs 3.6%; Odds ratio 0.54 (0.3 to 0.7); p <0.001, I2 = 77%]. Meta-regression showed lower mortality in smokers was associated with younger age, man gender, and lower prevalence of diabetes mellitus. No significant differences were observed in myocardial infarction, MACE, and target-vessel revascularization between smokers and nonsmokers. In conclusion, smoking is associated with lower mortality but not MACE in ACS patients treated with PCI at 1-month and 1-year. This association with mortality was strongly associated with younger age, man gender, prevalence of diabetes mellitus, and extent of coronary artery disease.