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Warfarin appears to remain effective choice for stroke risk reduction
Findings from a new meta-analysis suggest that warfarin is more effective for reducing stroke risk in patients with nonvalvular atrial fibrillation than was reported in an earlier meta-analysis.
Researchers at the Cleveland Clinic Heart and Vascular Institute analyzed eight large, contemporary, randomized controlled trials from 2001 to 2011 that included 32,053 patients who received 55,789 patient-years of warfarin therapy (Coumadin, Bristol-Myers Squibb) at follow-up. The researchers then performed a meta-analysis of safety and efficacy outcomes in patients with AF treated with warfarin for stroke prevention.
Patients prescribed warfarin had an estimated 1.66% annual incidence of stroke or systemic embolism compared with 2.09% in a similar meta-analysis that used data from 1989 to 1993. The researchers attributed this significant improvement to increased patient time spent in the international normalized ratio target range for receiving warfarin and to significantly better management of risk factors for atherosclerosis.
Results showed an increased annual incidence of stroke with increasing CHADS2 scores. The annual stroke risk was higher in females (2.12%); patients aged 75 years or older (2.27%); patients with a history of stroke (2.64%); and those who reported no exposure to treatments taken orally to reduce vitamin K in the system before enrollment in their respective studies (1.96%). Major bleeding rates varied from 1.4% to 3.4% per year across the studies examined.
The researchers said there are newer treatments that appear to be equal to or better than warfarin and easier to administer, but cost is a factor.
“Most patients with nonvalvular AF will probably continue to be treated with warfarin in the near future owing to cost considerations,” they said. “Indeed, warfarin will likely continue to be widely used as the drug of choice in several countries around the world.”
Disclosure: The researchers report no relevant financial disclosures.