Physicians' Health Study (Aspirin component) - Physicians' Health (Aspirin)


Low-dose aspirin for primary prevention of cardiovascular mortality.


Low dose aspirin decreases cardiovascular mortality.

Study Design

Study Design:

Patients Screened: Not given
Patients Enrolled: 22,071
Mean Follow Up: 60.2 months
Mean Patient Age: Not available
Female: 0

Patient Populations:

U.S. male physicians
40 to 84 years of age in 1982


History of cancer (except nonmelanoma skin cancer)
Myocardial infarction (MI)
Transient cerebral ischemia

Primary Endpoints:

Any type of malignant neoplasm except nonmelanoma skin cancer

Secondary Endpoints:

Myocardial infarction

Drug/Procedures Used:

Aspirin, 325mg, or placebo, taken on alternate days.

Concomitant Medications:

Beta-carotene capsules, 50 mg, or placebo, taken on alternate days (opposite the aspirin or placebo)

Principal Findings:

In the aspirin group, there was a 44% reduction in the risk of myocardial infarction (254.8 per 1000,000 per year vs 439.7 in the placebo group; relative risk, 0.56; 95% confidence interval, 0.45 to 0.70; p < 0.00001).

The reduction in the risk of myocardial infarction was apparent only among those 50 years of age and older.

The benefit of aspirin in reducing myocardial infarction was present at all levels of cholesterol, but appeared greatest at low levels.

A slightly increased risk of stroke in the aspirin group was not statistically significant. This trend was observed primarily in the subgroup with hemorrhagic stroke (relative risk 2.14; 95% confidence interval, 0.96 to 4.77; p = 0.06).

No reduction in mortality from all cardiovascular cases was associated with aspirin (relative risk, 0.96; 85% confidence interval, 0.60 to 1.54).
The relative risk of ulcer in the aspirin group was 1.22 (169 vs. 138; 95% confidence interval, 0.98 to 1.53; p = 0.08), and relative risk of requiring a blood transfusion was 1.71.

At 11.7 years, hypertension was associated with substantially increased risks of total cardiovascular disease (relative risk [RR] 1.92; 95% confidence interval [CI], 1.70 to 2.18), myocardial infarction (RR,1.78; 95% CI, 1.49 to 2.13), stroke (RR, 2.19; 95% CI, 1.78 to 2.69), and cardiovascular death (RR, 2.10; 95% CI, 1.68 to 2.63). Borderline isolated systolic hypertension was associated with significantly increased risks of cardiovascular disease (RR, 1.32; 95% CI, 1.09 to 1.59), stroke (RR, 1.42; 95% CI, 1.04 to 1.93), and cardiovascular death (RR, 1.56; 95% CI, 1.13 to 2.15).


This trial of aspirin for the primary prevention of cardiovascular disease demonstrates a conclusive reduction in the risk of myocardial infarction, but the evidence concerning stroke and total cardiovascular deaths remains inconclusive because of the inadequate numbers of physicians with those end points. Borderline isolated systolic hypertension is a significant risk factor for cardiovascular morbidity and mortality.


1. N Engl J Med 1989;321:129-35. Final results
2. Circulation 1997;95:1132-7. Hypertension (11.7 year follow-up)

Keywords: Blood Transfusion, Cholesterol, Myocardial Infarction, Stroke, Platelet Aggregation Inhibitors, Ulcer, Cardiovascular Diseases, Risk Factors, Confidence Intervals, Hypertension

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