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Prevention of cardiovascular disease: risks and benefits of aspirin
1Department of Medicine, Harvard Medical School, Boston, MA.
Insights
Aspirin significantly reduces major vascular events, including myocardial infarction (MI) and stroke, in secondary prevention and during acute MI. It also shows benefit in primary prevention of MI in men over 40.
Area of Science:
- Cardiology
- Preventive Medicine
- Clinical Trials
Background:
- Cardiovascular disease remains a leading cause of mortality worldwide.
- Aspirin is widely used, but its precise benefits across different patient populations require clear delineation.
- Randomized trials offer robust evidence for evaluating aspirin's efficacy in cardiovascular event prevention.
Purpose of the Study:
- To synthesize evidence from randomized trials on aspirin's effectiveness in preventing cardiovascular events.
- To assess aspirin's role in secondary prevention, acute myocardial infarction (MI) management, and primary prevention.
- To provide clear guidance on aspirin use for cardiovascular disease prevention.
Main Methods:
- Systematic review and meta-analysis of randomized controlled trials.
- Inclusion of trials in secondary prevention (post-MI, stroke, unstable angina), acute MI, and primary prevention populations.
- Stratified analysis based on patient categories and event types.
Main Results:
- In secondary prevention, aspirin significantly reduced "important vascular events" by 25%, nonfatal MI by 32%, nonfatal stroke by 27%, and vascular death by 15%.
- During acute MI, aspirin reduced vascular mortality by 23% and reinfarction rates.
- In primary prevention among men over 40, aspirin showed a 44% reduction in first MI, though stroke and vascular death data were inconclusive.
Conclusions:
- Aspirin is clearly beneficial for reducing MI, stroke, and vascular death in secondary prevention and acute MI settings.
- Aspirin demonstrates efficacy in the primary prevention of MI in men over 40.
- Further research is needed to clarify aspirin's impact on stroke and vascular death in primary prevention.
Abstract:
Aspirin has been tested for its benefit in preventing cardiovascular disease in randomized trials in three categories of patients. In secondary prevention among those with a history of myocardial infarction (MI), stroke or transient cerebral ischemia, or unstable angina pectoris, 25 randomized trials demonstrated significant reductions from aspirin of 25% for the occurrence of an "important vascular event" (nonfatal MI, nonfatal stroke, or vascular death), 32% for nonfatal MI, 27% for nonfatal stroke, and 15% for vascular mortality. Among those evolving an MI, the Second International Study of Infarct Survival (ISIS-2) showed a significant reduction of 23% in five-week vascular mortality among those started on a one-month regimen of daily aspirin within 24 hours of the onset of symptoms of suspected MI. Aspirin also significantly reduced reinfarction, nonfatal stroke, and important vascular events. Finally, in primary prevention, the US Physicians' Health Study (PHS) showed a significant 44% reduction in the occurrence of a first MI among apparently healthy male physicians; numbers of strokes and vascular deaths were insufficient to permit conclusions for these endpoints. Thus, aspirin is of clear benefit in reducing MI, stroke, and vascular death in secondary prevention and among those evolving an MI. It is also beneficial in the primary prevention of MI among men over 40, but data concerning its effects on stroke and vascular death remain inconclusive.