Effects of smoking on very-long term mortality after first ST elevation myocardial infarction

Background: The smoking paradox has been a matter of debate for acute myocardial infarction patients for more than two decades. Although there is huge evidence claiming that is no real paradox, publications supporting better outcomes in post-MI smokers are still being released. Objective: To explore the effect of smoking on very long-term mortality after ST Elevation myocardial infarction (STEMI). Methods: This study included STEMI patients who were diagnosed between the years of 2004-2006 at three tertiary centers. Patients were categorized according to tobacco exposure (Group 1: non-smokers; Group 2: <20 package⁎ years users, Group 3: 20-40 package⁎ years users, Group 4: >40 package⁎ years users). A Cox regression model was used to estimate the relative risks for very long-term mortality. P value <0.05 was considered as statistically significant. Results: There were 313 patients (201 smokers, 112 non-smokers) who were followed-up for a median period of 174 months. Smokers were younger (54±9 vs. 62±11, p: <0.001), and the presence of cardiometabolic risk factors were more prevalent in non-smokers. A univariate analysis of the impact of the smoking habit on mortality revealed a better survival curve in Group 2 than in Group 1. However, after adjustment for confounders, it was observed that smokers had a significantly increased risk of death. The relative risk became higher with increased exposure (Group 2 vs. Group 1; HR: 1.141; 95% CI: 0.599 to 2.171, Group 3 vs Group 1; HR: 2.130; 95% CI: 1.236 to 3.670, Group 4 vs Group 1; HR: 2.602; 95% CI: 1.461 to 4.634). Conclusion: Smoking gradually increases the risk of all-cause mortality after STEMI. (author)