The association between smoking and long-term outcomes after non-ST-segment elevation myocardial infarction in older patients

Background Prior studies have observed that smokers have paradoxically favorable 1-year mortality rates after acute coronary syndromes, but it is unknown whether this association extends to long-term outcomes and to older patients. Methods We identified 38,628 patients aged ≥65 years participating in the CRUSADE Registry between February 2003 and December 2006 with non-ST-segment elevation myocardial infarction and linked these patients to Medicare claims data to assess longitudinal outcomes. Cox proportional hazard models were used to examine the association between smoking, 30-day, and long-term outcomes. Results Overall, 4,876 (13%) were current/recent smokers and 33,752 (87%) were nonsmokers. Compared with nonsmokers, smokers were younger and more likely to be male and to receive in-hospital revascularization (all P <.001) but less likely to have hypertension, diabetes mellitus, and renal insufficiency. Compared with nonsmokers, the unadjusted 30-day mortality was lower (8.7% vs 10.3%, P =.0004), but the adjusted 30-day mortality was similar (adjusted hazard ratio [HR] 1.08, 95% CI 0.97-1.20). Over a median of 3.6 years of follow-up, smokers had lower crude long-term mortality rates (53% vs 55% at 6 years, P =.001) but significantly higher long-term mortality rates after adjustment (adjusted HR 1.28, 95% CI 1.21-1.34). Smokers also had higher risks of all-cause readmission (HR 1.13, 95% CI 1.09-1.17) and recurrent myocardial infarction (HR 1.23, 95% CI 1.13-1.34). Conclusions Among older non-ST-segment elevation myocardial infarction patients, we found that smokers had significantly higher long-term risks for both mortality and recurrent myocardial infarction. These results support ongoing efforts to promote smoking cessation, even among older patients.