Wide Variation in Reported Rates of Stroke Across Cohorts of Patients With Atrial Fibrillation

Background:Oral anticoagulants decrease ischemic stroke rates in patients with atrial fibrillation (AF) but increase the risk of bleeding. For the average patient with AF, the threshold of annual ischemic stroke rate where the benefit of anticoagulation outweighs the bleeding risk (net clinical benefit) has been shown to be ≈1% to 2%. Guideline recommendations for oral anticoagulants in AF are based on the CHA2DS2-VASc stroke risk point scores, assuming that those scores translate to fixed stroke rates. However, the relationship between stroke point scores and annual stroke rates may vary substantially across populations. We sought to comprehensively assess the reported rates of stroke in patients with AF and the relationship of stroke rates to stroke risk point scores. Methods:A systematic review of cohort studies and randomized controlled trials enrolled patients with nonvalvular AF not treated with oral anticoagulants. Results:Of the 3552 studies screened, we identified 34 studies eligible for analysis...