Effect of antiplatelet therapy on vascular events

Category of trial	Number of trials with data	Antiplatelet, %*	Adjusted controls, %*	Odds reduction, %^¶
Prior MI	12	13.5	17	25±4
Acute MI	15	10.4	14.2	30±4
Prior stroke/TIA	21	17.8	21.4	22±4
Acute stroke	7	8.2	9.1	11±3
Other high risk	140	8	10.2	26±3
Unstable angina	12	8	13.3	46±7
Stable angina/CHD	7	9.9	14.1	33±9
Peripheral arterial disease	42	5.8	7.1	23±8
All trials (high or low risk)	195	10.7	13.2	22±2
All low risk^Δ (primary prevention)	3	4.5	4.9	10

MI: myocardial infarction; TIA: transient ischemic attack; CHD: coronary heart disease.
* Percent of patients suffering vascular events who are treated with antiplatelet agents or placebo; the duration of treatment was 2 years with a prior MI or stroke/TIA, 30 days with an acute MI, 3 weeks with an acute stroke, and 2 years for other high-risk patients.
¶ Odds reduction of vascular events due to antiplatelet therapy.
Δ Data from: Antiplatelet Trialists' Collaboration. BMJ 1994; 308:81.

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