- Question
- Does low-dose aspirin reduce cardiovascular events in patients at moderate cardiovascular risk without prior disease (primary prevention), and at what safety cost?
- Design
- Randomised 1:1, double-blind, placebo-controlled, multicentre trial conducted in seven countries (501 sites). It enrolled 12546 patients, with a median follow-up of 60 months.
- Population
- Men aged 55 years or older and women aged 60 years or older with average cardiovascular risk, deemed moderate based on the number of specific risk factors. Patients at high risk of gastrointestinal or other bleeding, and those with diabetes, were excluded.
- Intervention
- Enteric-coated aspirin 100 mg once daily (6270 patients).
- Control
- Matching placebo tablet once daily (6276 patients).
- Primary outcome
- Time to first occurrence of the composite of cardiovascular death, myocardial infarction, unstable angina, stroke or transient ischaemic attack.
- Results
- The primary endpoint occurred in 269 patients (4.29%) with aspirin and 281 (4.48%) with placebo (HR 0.96; 95% CI 0.81-1.13; P=0.6038), with no significant difference. Mortality was similar between groups (2.55% vs 2.57%).
- Safety
- Gastrointestinal bleeding events, mostly mild, were more frequent with aspirin (61 patients, 0.97%) than with placebo (29 patients, 0.46%; HR 2.11; 95% CI 1.36-3.28; P=0.0007). The incidence of serious adverse events was similar between groups (20.19% vs 20.89%).
- Conclusion
- In patients at moderate cardiovascular risk, low-dose aspirin did not significantly reduce cardiovascular events and increased gastrointestinal bleeding.
- Why it matters
- The event rate was much lower than expected, so the trial ended up representing a low-risk population and could not fully answer the question in moderate risk. Nonetheless, its results were consistent with other primary prevention trials and reinforced caution about routine aspirin use in this population.
Card generated automatically with AI from the abstract of the original publication and the trial registry; every figure was checked against those sources. It may contain errors: verify the data at the source before using it for clinical decisions.
Generated on October 18, 2026