Atrial Fibrillation: Apixaban versus Rivaroxaban

Atrial Fibrillation: Apixaban versus Rivaroxaban
David Bunch, Pharm.D., Smiley’s Family Medicine

Background: Direct oral anticoagulants (DOACs) are commonly used to prevent thromboembolic events in patients with atrial fibrillation, with apixaban and rivaroxaban being the most common medications used in this class. While the 2018 CHEST guidelines on atrial fibrillation recommended DOAC use over warfarin, there is little head to head evidence between the DOACs.

Purpose: To compare the safety and efficacy of apixaban versus rivaroxaban for the prevention of thromboembolic events in patients with nonvalvular atrial fibrillation.

Study Design: This study was a retrospective, active-comparator cohort study that used a nationwide commercial insurance claims database. This study compared patients aged 18 years and older who had a diagnosis of atrial fibrillation or atrial flutter and who had received a new prescription for apixaban 5 mg or rivaroxaban 20 mg between December 28, 2012 and January 1, 2019. Date of entry for inclusion in the analysis was considered to be the date of the first prescription for apixaban or rivaroxaban. Patients were excluded if they had any of the following characteristics within 180 days of starting the medication: stage 5 chronic kidney disease requiring dialysis, cancer, valvular heart disease, venous thromboembolism, hip surgery, or knee surgery. The primary effectiveness outcome was a composite of ischemic stroke or systemic embolism and the primary safety outcome was a composite of gastrointestinal bleeding or intracranial hemorrhage.

Results: Patients were divided into groups via 1:1 propensity score matching.In total, the study analyzed 78,702 patients with 39,351 patients in each arm of the study. Mean follow-up for apixaban was 288 days and 291 days for rivaroxaban. The patients in the apixaban group were slightly older, had more diagnoses of kidney or cardiovascular disease, and were receiving slightly more medications at baseline. Fewer patients in the rivaroxaban group had a history of smoking or hyperlipidemia and more had received warfarin in the preceding 30 days. After propensity score matching, 206 patients in the apixaban group had the primary outcome or 6.6 events per 1000 person-years compared to 251 patients in the rivaroxaban group or 8.0 events per 1000 person-years, 0.82 [95% CI, 0.68 - 0.98]. A subgroup analysis for patients older than 70 years old was conducted and in this subgroup 132 patients had the primary outcome in the apixaban group (8.3 events per 1000 person years) and 165 patients had the primary outcome in the rivaroxaban group (10.5 events per 1000 person years) 0.79 [95% CI, 0.63 - 0.99]. In regards to the primary safety outcome, after propensity score matching, the rate of major bleeding was 401 events or 12.9 per 1000 person years for apixaban and 685 events or 21.9 per 1000 person years for rivaroxaban, 0.58 [95% CI 0.52 - 0.66].

Conclusions: This retrospective cohort study suggests that apixaban is more likely to prevent a stroke or systemic embolism and is less likely to cause a major bleed than rivaroxaban for patients with nonvalvular atrial fibrillation. Interestingly, the subgroup of patients greater than 70 years old (a population that would be at greater risk for an embolic event and major bleed) also showed significance for apixaban over rivaroxaban. Until head to head randomized controlled trials are conducted on these medications, the results presented in this study support apixaban use over rivaroxaban when available.

Key Point: In patients with atrial fibrillation, apixaban may be safer and more effective than rivaroxaban due to results from a retrospective analysis.

References:

  1. Fralick, M., Colacci, M., Schneeweiss, S., etal. Effectiveness and Safety of Apixaban Compared With Rivaroxaban for Patients With Atrial Fibrillation in Routine Practice. Ann Intern Med. 2020;172(7), p.463.

  2. Lip, G., Banerjee, A., Boriani, G., et al. Antithrombotic Therapy for Atrial Fibrillation. Chest. 2018;154(5), pp.1121-1201.