Effect of cigarette smoking on survival of patients with angiographically documented coronary artery disease. Report from the CASS registry.

Through a multicenter registry of patients in the Coronary Artery Surgery Study, we prospectively evaluated morbidity and mortality in 4,165 smokers with angiographically proved coronary artery disease, 2,675 of whom continued to smoke and 1,490 of whom quit. At five years, mortality (adjusted by Cox analysis for baseline differences) was 22% for those who continued smoking and 15% for quitters. The relative risk (also from the Cox analysis) for mortality in continuers vs quitters was 1.55 (95% confidence interval, 1.29 to 1.85). The adverse effect of smoking mainly took the form of higher frequencies of myocardial infarction--associated death and sudden death: the frequencies of these events during follow-up in continuers vs quitters were 7.9% vs 4.4% for myocardial infarction--associated death and 2.8% vs 1.5% for sudden death. This study supports the recommendation that patients with coronary artery disease should stop smoking.