Influence of cessation of smoking on long term mortality in patients with coronary heart disease.

Cessation of smoking in patients with coronary artery disease (CAD) has shown variable results. The long term mortality in patients of coronary heart disease (CHD) who quit smoking following diagnosis of their disease has been variable. We have analysed the long term effects of cessation of smoking on mortality in a cohort of 173 patients with CAD and compared the mortality of this group with 299 nonsmokers and 52 current smokers. The baseline data were identical for major risk factors like age, hypertension, diabetes, cholesterol levels, and congestive heart failure among the three groups (p > 0.1). There were more patients with previous myocardial infarction in past (38.7%) and current smokers (40.4%) than among nonsmokers (25.4%). All patients were followed for a period extending upto 11 years. The mean duration of follow up was 6.81 +/- 2.95 years in non-smokers, 5.98 +/- 2.94 years in exsmokers, and 6.32 +/- 3.44 years in current smokers. Actuarial analysis shows that overall mortality was significantly more among exsmokers than nonsmokers (Logrank test = 3.72, 1p < 0.05). The exsmokers showed similar mortality as current smokers during the first three years of follow up (Logrank test = 1.10, 1p < 0.1); but afterwards the mortality was significantly less in exsmokers than in current smokers (Logrank test = 6.29, 1p < 0.025). However, the overall mortality was lowest in nonsmokers when compared to that of exsmokers and current smokers (Logrank test = 3.92, p < 0.05). The total mortality was 28.1% in nonsmokers, 32.4% in exsmokers, and 46.2% in current smokers. The incidence of sudden death was, however, similar in all the groups.(ABSTRACT TRUNCATED AT 250 WORDS)