Evaluation of the benefits and risks of low-dose aspirin in the secondary prevention of cardiovascular and cerebrovascular events.

BACKGROUND

In spite of the clear evidence of benefit of aspirin in the secondary prevention of cerebrovascular and cardiovascular thrombotic events, its use in patients at high risk due to a previous event remains suboptimal. A possible explanation for this underuse is concern regarding the relative benefit in relation to the potential risk for serious gastrointestinal events.

OBJECTIVE

To compare the benefit and gastrointestinal risk of aspirin use for the secondary prevention of thromboembolic events.

DESIGN

A meta-analysis was conducted using 6 trials (6300 patients) meeting the inclusion requirement of use of low-dose aspirin (< or =325 mg/d) in approved secondary prevention indications.

RESULTS

Aspirin reduced all-cause mortality by 18%. In addition, aspirin use reduced the number of strokes by 20%, myocardial infarctions by 30%, and other "vascular events" by 30%. Alternately, patients who took aspirin were 2.5 times more likely than those in the placebo group to have gastrointestinal tract bleeding. The number needed to treat for aspirin to prevent 1 death from any cause of mortality was 67, while 100 needed to be treated to detect 1 nonfatal gastrointestinal tract bleeding.

CONCLUSION

Aspirin use for the secondary prevention of thromboembolic events has a favorable benefit-to-risk profile and should be encouraged in those at high risk.