Study: Standard Apixaban Dose Safe for Certain High-Risk A-Fib Patients

The risk of major bleeding is lower in patients with atrial fibrillation taking apixaban than in those taking warfarin, regardless of their age, body weight, and creatinine levels, according to a recent study.

In the Apixaban for Reduction of Stroke and Other Thromboembolic Complications in Atrial Fibrillation (ARISTOTLE) trial, participants were given a standard dose of 5 mg twice daily, and those with at least 2 dose-reduction criteria (aged 80 years or older, weight 60 kg or less, and creatinine levels of 1.5 mg/dL or higher) received only 2.5 mg twice daily. While the study examined the effects of this lower dose in these patients, little is known about the effects of the full 5-mg dose in patients with 1 dose-reduction criterion.
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In a secondary analysis of the ARISTOTLE trial, researchers sought to determine the effects of a 5-mg twice-daily dose of apixaban on stroke or systemic embolism and bleeding among those with 1 dose-reduction criterion.

The researchers included 17,322 of the 18,201 participants from the ARISTOTLE trial in their analysis. Overall, of the patients with 1 or no dose-reduction criteria assigned 5 mg twice daily of apixaban or warfarin, 3966 had 1 dose-reduction criterion. These participants had higher rates of stroke and systemic embolism and major bleeding compared with those with no dose-reduction criterion.

The benefits of the 5-mg dose of apixaban compared with warfarin on stroke, systemic embolism, and major bleeding in those with 1 dose-reduction criterion and no dose-reduction criterion were similar.

“Patients with atrial fibrillation and isolated advanced age, low body weight, or renal dysfunction have a higher risk of stroke or systemic embolism and major bleeding but show consistent benefits with the 5 mg twice daily dose of apixaban vs warfarin compared with patients without these characteristics. The 5 mg twice daily dose of apixaban is safe, efficacious, and appropriate for patients with only 1 dose-reduction criterion,” the researchers concluded.

—Michael Potts

Reference:
Alexander JH, Andersson U, Lopes RD, et al. Apixaban 5 mg twice daily and clinical outcomes in patients with atrial fibrillation and advanced age, low body weight, or high creatinine: a secondary analysis of a randomized clinical trial [published online July 27, 2016]. JAMA. doi:10.1001/jamacardio.2016.1829.