Smoker pseudo-paradox in ST-segment elevation myocardial infarction patients

Abstract

Introduction: Cigarette smoking is a preventable cause of cardiovascular morbidity and mortality. Despite the adverse effects of smoking, some studies have reported the term “smoker’s paradox’, meaning better outcomes in smokers following acute myocardial infarction.Aim: The aim of the present study was to evaluate the relationship between smoking status and one-year mortality in patients with ST-segment elevation myocardial infarction (STEMI).Materials and methods: This was a registry-based cohort study of STEMI patients from Imam-Ali hospital, Kermanshah, Iran. Consecutive STEMI patients (July 2016-October 2018) were stratified by smoking status and followed for one year. Cox proportional models were used to estimate crude, age-adjusted, and full-adjusted hazard ratios with 95% confidence intervals (HR, 95%CI).Results: Of 1975 patients (mean age 60.1 years, 76.6% male) included in the study, 48.1% (n=951) were smokers (mean age 57.7 years, 94.7% male). Crude and age-adjusted HR (95% CI) for the associations of smoking and mortality were 0.67 (0.50-0.92) and 0.89 (0.65-1.22), respectively. After adjusting for age, sex, hypertension, diabetes, body-mass index, anterior wall myocardial infarction, creatine kinase-MB, glomerular filtration rate, left ventricular ejection fraction, low-density lipoprotein cholesterol, and hemoglobin, smoking was associated with increased risk of mortality: HR (95% CI: 1.56 (1.04-2.35).Conclusions: In our study, smoking was associated with an increased risk of mortality. Although the smokers had a better outcome, this would be reversed after controlling for age and the other STEMI associated factors.

Keywords

• smoker’s paradox
• cigarette smoking
• ST-elevation