Apixaban Not Superior to Warfarin for Reducing Stroke Risk in Atrial Fibrillation
Researchers sought to compare apixaban with warfarin, dabigatran, and rivaroxaban for stroke prevention in atrial fibrillation.
Apixaban and warfarin are equally effective in reducing the incidence of stroke and thromboembolic events among patients with atrial fibrillation, according to findings from a systematic review and meta-analysis published in Stroke.
A total of 16 studies with 170,814 apixaban-treated patients were included in the final analysis. In 4 studies, apixaban was compared with warfarin; in 8 studies, apixaban use was compared with warfarin, dabigatran, and rivaroxaban; and in the remaining 4 studies, apixaban was compared with both dabigatran and rivaroxaban.
According to the findings from the meta-analysis, a regular dose of apixaban was more effective in reducing any thromboembolic event (odds ratio [OR], 0.77; 95% CI, 0.64-0.93) than warfarin. Despite this apparent benefit, the patients in the reduced dose subgroup had an overall 27% increase in risk for any thromboembolic event (P <.0001).
Risk for hemorrhagic stroke was also significantly reduced among patients taking apixaban (36% relative risk reduction [RRR]; P =.0003). In addition, the risks for major bleeding (OR, 0.62; 95% CI, 0.51-0.75) and any bleeding (P =.009) were lower in the apixaban vs warfarin groups. Nonsignificant differences were found between apixaban and dabigatran in the risk for any thromboembolic event (P =.30).
In addition, patients taking apixaban had lower gastrointestinal bleeding (57% RRR; P <.00001) and lower rates of any bleeding (31% RRR; P <.00001) compared with patients taking dabigatran. Although rivaroxaban was superior to apixaban in terms of a lower risk for any thromboembolic event (OR, 1.27; 95% CI, 1.13-1.43) and stroke (OR, 1.31; 95% CI, 1.15-1.50), apixaban was associated with a lower risk for major bleeding compared with rivaroxaban (46% RRR; P <.00001).
A limitation associated with this study included the investigators' inability to account for the quality of anticoagulation control or patient adherence to nonvitamin K antagonist oral anticoagulants.
Overall, the similar efficacy and safety profiles of the studied therapies "suggest that in the context of currently available [real-world studies] evidence apixaban could possibly represent the best alternative for [oral anticoagulant therapy]...for many patients with [atrial fibrillation]."
Proietti M, Romanazzi I, Romiti GF, Farcomeni A, Lip GYH. Real-world use of apixaban for stroke prevention in atrial fibrillation: a systematic review and meta-analysis [published online November 22, 2017]. Stroke. doi:10.1161/STROKEAHA.117.018395