The natural history of prevalent ischaemic heart disease in middle-aged men.

Objective: To describe the long-term outcome of different forms of symptomatic and asymptomatic ischaemic heart disease in middle-aged men.
Methods: 7735 men aged 40-59, randomly selected from 24 general practices in Britain were classified into one of seven ischaemic heart disease groups according to a questionnaire and electrocardiogram (ECG): I=diagnosed myocardial infarction; II=unrecognized myocardial infarction; III= diagnosed angina; IV=angina symptoms; V=possible myocardial infarction symptoms; VI=ECG ischaemia or possible myocardial infarction; VII=no evidence of ischaemic heart disease. The association of disease group with a range of fatal and non-fatal outcomes during 15 years of follow-up was assessed.
Results: At baseline 25% of men had evidence of ischaemic heart disease (groups I-VI). Risks of major ischaemic heart disease events, total and cardiovascular mortality, stroke, and major cardiovascular events tended to increase strongly from group VII to I. Diagnosed myocardial infarction was associated with a much poorer prognosis than all other groups (including unrecognized infarction) for all cardiovascular outcomes other than stroke. The relative risk associated with ischaemic heart disease at baseline declined dramatically over time. However, men with myocardial infarction who survived event-free for 10 years continued to experience a high excess risk in the subsequent 5 years, in contrast to event-free survivors of angina and other ischaemic heart disease. Adjusted to an average age of 50, the percentage of men surviving for 15 years free of a new major cardiovascular event was 44 for diagnosed myocardial infarction, 52 for unrecognized myocardial infarction, 66 for diagnosed angina, 68 for angina symptoms, 73 for possible myocardial infarction symptoms, 73 for ECG ischaemia, and 79 for no ischaemic heart disease. Comparison of outcome between prevalent and incident myocardial infarction illustrated the improved prognosis of men surviving the initial years after their event.
Conclusions: Differing manifestations of prevalent ischaemic heart disease are associated with widely differing outcome, and the majority of middle-aged men in the community who have evidence of ischaemic heart disease short of myocardial infarction survive for 15 years without heart attack or stroke. The excess risk associated with myocardial infarction appears more persistent than that associated with angina and other ischaemic heart disease, remaining high even after 10 years of event-free survival.