(HealthDay News) – Use of warfarin for stroke prevention in patients with nonvalvular atrial fibrillation (AF) is associated with a low risk of stroke or systemic embolism.

Shikhar Agarwal, MD, MPH, from the Cleveland Clinic, and colleagues conducted a literature review and meta-analysis of randomized controlled trials to assess warfarin treatment for stroke prevention in patients with AF. Eligible studies compared warfarin with an alternative thromboprophylaxis strategy, included at least 400 patients in the warfarin arm, and reported stroke as an efficacy outcome.

The researchers found that the eight eligible studies included 55,789 patient-years of warfarin therapy follow-up. For patients with AF taking warfarin, the annual incidence of stroke or systemic embolism was estimated to be 1.66%, while rates of major bleeding ranged across the studies, from 1.4–3.4% per year. There was a significantly higher stroke risk per year for elderly patients (2.27%), female patients (2.12%), patients with a history of stroke (2.64%), and patients with no previous exposure to vitamin K antagonists (1.96%). The annual incidence of stroke was significantly increased with progressively increasing scores of CHADS2 (congestive heart failure, hypertension, age, diabetes, and prior stroke).

“Current use of warfarin as a stroke prevention agent in patients with AF is associated with a low rate of residual stroke or systemic embolism estimated to be 1.66% per year,” the authors write.

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