Background: The effect of cholesterol-lowering therapy on death from coronary heart disease in older patients with previous coronary heart disease and average cholesterol levels is uncertain.
Objective: To compare the relative and absolute effects of pravastatin on cardiovascular disease outcomes in patients with coronary heart disease who are 65 years of age or older with those in patients 31 to 64 years of age.
Design: Subgroup analysis of a randomized, placebo-controlled trial.
Setting: 87 centers in Australia and New Zealand.
Patients: 3514 patients 65 to 75 years of age, chosen from among 9014 patients with previous myocardial infarction or unstable angina and a baseline plasma cholesterol level of 4.0 to 7.0 mmol/L (155 to 271 mg/dL).
Intervention: Pravastatin, 40 mg/d, or placebo.
Measurements: Major cardiovascular disease events over 6 years.
Results: Older patients were at greater risk than younger patients (31 to 64 years of age) for death (20.6% vs. 9.8%), myocardial infarction (11.4% vs. 9.5%), unstable angina (26.7% vs. 23.2%), and stroke (6.7% vs. 3.1%) (all P < 0.001). Pravastatin reduced the risk for all cardiovascular disease events, and similar relative effects were observed in older and younger patients. In patients 65 to 75 years of age, pravastatin therapy reduced mortality by 21% (CI, 7% to 32%), death from coronary heart disease by 24% (CI, 7% to 38%), coronary heart disease death or nonfatal myocardial infarction by 22% (CI, 9% to 34%), myocardial infarction by 26% (CI, 9% to 40%), and stroke by 12% (CI, -15% to 32%). For every 1000 older patients treated over 6 years, pravastatin prevented 45 deaths, 33 myocardial infarctions, 32 unstable angina events, 34 coronary revascularization procedures, 13 strokes, or 133 major cardiovascular events, compared with 22 deaths and 107 major cardiovascular events per 1000 younger patients. Among older patients, the numbers needed to treat were 22 (CI, 17 to 36) to prevent one death from any cause, 35 (CI, 24 to 67) to prevent one death from coronary heart disease, and 21 (CI, 17 to 31) to prevent one coronary heart disease death or nonfatal myocardial infarction.
Conclusions: In older patients with coronary heart disease and average or moderately elevated cholesterol levels, pravastatin therapy reduced the risk for all major cardiovascular events and all-cause mortality. Since older patients are at greater risk than younger patients for these events, the absolute benefit of treatment is significantly greater in older patients.