Antithrombotic treatment for the primary prevention of stroke in patients with non valvular atrial fibrillation: A reappraisal of the evidence and network meta analysis

The role of aspirin for the primary prevention of stroke in patients with non valvular atrial fibrillation is critically reviewed. It is shown that the currently held belief that aspirin (at doses of 75 to 325 mg daily) is an effective treatment is based on a flawed interpretation of the data. A Bayesian network meta analysis is presented that demonstrates that aspirin at 325 mg daily is superior to control and similar to warfarin for the reduction of the risk of both stroke and death. In contrast for lower daily doses of aspirin there is no evidence of any efficacy over control for the reduction of the risk of stroke. The data are inconclusive as to whether lower doses of aspirin may have some benefit in reducing the risk of death.