Clinical characteristics and cigarette smoking in relation to prognosis of angina pectoris in Framingham.
A long-term follow-up study of 130 Framingham, Massachusetts, men with newly diagnosed uncomplicated angina pectoris was undertaken in an attempt to identify medical and personal characteristics which could predict the likelihood of a future coronary event. Analyses indicated that, among the baseline characteristics, systolic blood pressure and electrocardiographic findings were the most powerful independent predictors of the outcome. Elevated blood pressure or an abnormal electrocardiogram increased coronary risk more than twofold. The lack of association between smoking at diagnosis and a new event appeared to be related to changes in habits after angina onset. Further scrutiny of the data indicated that, irrespective of blood pressure and electrocardiographic findings, those less than 60 years of age at angina onset who were nonsmokers or quitters during follow-up had a definite prognostic advantage over similarly aged continuing smokers. These results could not be explained by differences in coronary risk factors prior to symptom onset or by changes in factors other than smoking during follow-up. The findings suggest that stopping the cigarette smoking habit can improve both short-term and long-term prognosis in the younger patient and angina pectoris.