Long-term prognosis after recovery from myocardial infarction: a nine year follow-up of the Perth Coronary Register.

Patients registered by the 1971 Perth Coronary Register as having suffered a myocardial infarction were followed up for 9 years. The Register was a community-based study that used standard methods and criteria as part of a World Health Organization collaborative investigation. Of the 1078 patients studied, 77% survived the first 24 hr and 62% the first 28 days; 0.3% were lost to follow-up. For the 666 patients alive at 28 days, the crude 1, 5, and 9 year survival rates were 88%, 67%, and 52%, respectively. The relationship between 54 variables and the survival of patients alive 28 days after myocardial infarction was examined by life-table methods and the log rank test, and then by fitting a proportional hazards model to the data. The important prognostic factors were age, sex, past history of myocardial infarction, stroke, diabetes and hypertension, tachycardia at presentation, hypotension at presentation, and the occurrence of arrhythmias as short-term complications. The most appropriate mathematical description of the joint effects of the prognostic factors was a multiplicative model with no interaction.