- Aspirin users free of cardiovascular disease did not have a significant reduction in stroke overall or nonfatal stroke, and showed an increase in hemorrhagic stroke.
Why this matters
- About 4 in 5 aspirin users report taking the medication for primary prevention, with two-thirds believing it prevents stroke.
- Compared with nonusers, aspirin users did not have significant reduction in risks for:
- All stroke (OR, 0.95; 95% CI, 0.88-1.03).
- Nonfatal stroke (OR, 0.94; 95% CI, 0.85-1.04).
- All-cause mortality (OR, 0.97; 95% CI, 0.92-1.03).
- Cardiovascular mortality (OR, 0.94; 95% CI, 0.85-1.03).
- Users had increased risks for:
- Hemorrhagic stroke (OR, 1.29; 95% CI, 1.06-1.56).
- Major gastrointestinal bleeding (OR, 1.83; 95% CI, 1.43-2.35).
- Users had reduced risk for nonfatal myocardial infarction (OR, 0.80; 95% CI, 0.69-0.94).
- When nonfatal events (myocardial infarction, stroke), major bleeding were equally weighted, aspirin did not have net clinical benefit.
- Meta-analysis of 11 randomized controlled trials of aspirin vs placebo for primary prevention of cardiovascular disease among 157,054 adults, follow-up >1 year.
- Main outcomes: cardiovascular outcomes.
- Funding: Irish Clinical Academic Training Programme, supported by Wellcome Trust, others.
- Exclusion of trials not reporting on stroke.
- Heterogeneity across trials.
- Some did not require imaging for stroke diagnosis.