Design and baseline characteristics of the xarelto post-authorization safety & effectiveness study in Japanese patients with atrial fibrillation (Xapass)

Background: The phase III Japanese Rivaroxaban Once-Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (J-ROCKET AF) showed that the rivaroxaban group had a lower event rate of intracranial bleeding than the warfarin group and that rivaroxaban was noninferior to warfarin for the principal safety outcome. However, safety and effectiveness data from unselected patients with AF in everyday clinical practice in Japan are lacking. Methods: The Xarelto Post-Authorization Safety & Effectiveness Study in Japanese Patients with Atrial Fibrillation (XAPASS) is a real-world, prospective, single-arm, observational study mandated by the Japanese authority as postmarketing surveillance. XAPASS involves patients with nonvalvular AF prescribed rivaroxaban. The principal safety outcome is a composite of major and nonmajor bleeding events, and the primary effectiveness outcome is the incidence of ischemic stroke, hemorrhagic stroke, noncentral nervous system systemic embolism, and myocardial infarction. Results: In total, 11 308 patients were enrolled from April 2012 to June 2014. Their age was 73.1 ± 9.9 years, and their CHADS2 score was 2.2 ± 1.3. Female patients, patients aged ≥75 years, patients with a body weight of ≤50 kg, and patients with a creatinine clearance of <50 mL/min constituted 38.1%, 48.7%, 19.5%, and 23.9% of all patients, respectively. Almost half (53.2%) of patients were prescribed other anticoagulants before starting rivaroxaban. Conclusions: Data from this study will supplement those from the J-ROCKET AF and provide practical information for the optimal use of rivaroxaban for stroke prevention in Japanese patients with AF (Clinicaltrials.gov: NCT01582737).