Smoking and cardiovascular outcomes after percutaneous coronary intervention: a Korean study

BACKGROUND AND AIMS: The authors investigated the impact of smoking and its cessation after percutaneous coronary intervention (PCI) on cardiovascular outcomes. METHODS: Using a nationwide database from the Korean National Health Insurance System, 74 471 patients undergoing PCI between 2009 and 2016 were classified as non-, ex-, or current smokers, depending on smoking status at the first health check-up within 1 year after PCI. The primary outcome was major adverse cardiovascular and cerebrovascular event (MACCE), a composite of all-cause death, myocardial infarction, coronary revascularization, and stroke. RESULTS: During 4.0 years of follow-up, current smokers had a 19.8% higher rate of MACCE than non-smokers adjusted hazard ratio (aHR) 1.198; 95% confidence interval (CI) 1.137-1.263, and ex-smokers tended to have a comparable rate with that of non-smokers (aHR 1.036; 95% CI .992-1.081). For 31 887 patients with both pre- and post-PCI health check-up data, the effects of smoking cessation were analysed. Among quitters who stopped smoking after PCI, quitters with cumulative smoking exposure of <20 pack-years (PYs) tended to have a comparable rate of MACCE with that of persistent non-smokers. However, the rate in quitters with cumulative exposure of ≥20 PYs was comparable with that of persistent smokers aHR (95% CI) for <10 PY, 1.182 (.971-1.438); 10-20 PYs 1.114 (.963-1.290); 20-30 PYs 1.206 (1.054-1.380); ≥ 30 PYs 1.227 (1.113-1.352); persistent smokers 1.223 (1.126-1.328), compared with persistent non-smokers, respectively, P for interaction <.001. CONCLUSIONS: Smoking is associated with a higher risk of adverse outcomes in patients undergoing PCI. Quitters after PCI with <20 PYs were associated with a risk comparable with that of non-smokers.