Aspirin or other antiplatelet vs placebo or no treatment

Study population:

Secondary prevention of CVD in patients with history of stroke or TIA (outwith acute period)

Comments:

Antiplatelets included aspirin (most widely studied), clopidogrel, dipyridamole, and other antiplatelets not commonly used in UK practice.

Outcome	Duration	NNT	Annualised NNT
Serious vascular event. (Defined as non-fatal MI, non-fatal stroke or vascular death).	29 -31 months	28-40	68-94

References

Antithrombotic trialists collaboration. Collaborative meta-analysis of randomised trials of antiplatelet therapy for prevention of death, MI and stroke in high risk patients. BMJ 2002;358:71-86

McGrath E et al. Validity of composite outcomes in meta-analyses of stroke prevention trials: the case of aspirin. Cerebrovascular Diseases 2011; 32(1):22-7.