Clinical Outcomes With Rivaroxaban in Patients Transitioned From Vitamin K Antagonist Therapy

BACKGROUND In ROCKET AF (Rivaroxaban Once-Daily, Oral, Direct Factor Xa Inhibition Compared With Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation), a large randomized, clinical trial, rivaroxaban was noninferior to warfarin in preventing stroke or systemic embolism in patients with atrial fibrillation. OBJECTIVE To determine the efficacy and safety of rivaroxaban compared with warfarin among vitamin K antagonist (VKA)-naive and VKA-experienced patients. DESIGN Prespecified subgroup analysis. (ClinicalTrials.gov: NCT00403767). SETTING Global. PATIENTS 14,264 persons with atrial fibrillation. MEASUREMENTS Interaction of the relative treatment effect of rivaroxaban and warfarin on stroke or systemic embolism among VKA-naive and VKA-experienced patients. RESULTS Overall, 7897 (55.4%) patients were VKA-experienced and 6367 (44.6%) were VKA-naive. The effect of rivaroxaban versus warfarin on stroke or systemic embolism was consistent: Rates per 100 patient-years of follow-up were 2.32 versus 2.87 for VKA-naive patients (hazard ratio [HR], 0.81 [95% CI, 0.64 to 1.03]) and 1.98 versus 2.09 for VKA-experienced patients (HR, 0.94 [CI, 0.75 to 1.18]; interaction P = 0.36). During the first 7 days, rivaroxaban was associated with more bleeding than warfarin (HR in VKA-naive patients, 5.83 [CI, 3.25 to 10.44], and in VKA-experienced patients, 6.66 [CI, 3.83 to 11.58]; interaction P = 0.53). After 30 days, rivaroxaban was associated with less bleeding than warfarin in VKA-naive patients (HR, 0.84 [CI, 0.74 to 0.95]) and similar bleeding in VKA-experienced patients (HR, 1.06 [CI, 0.96 to 1.17]; interaction P = 0.003). LIMITATION The trial was not designed to detect differences in these subgroups. CONCLUSION The efficacy of rivaroxaban in VKA-experienced and VKA-naive patients was similar to that of the overall trial. There were more bleeding events within 7 days of study drug initiation with rivaroxaban, but after 30 days, rivaroxaban was associated with less bleeding in VKA-naive patients and similar bleeding in VKA-experienced patients. This information may be useful to clinicians considering a transition to rivaroxaban for patients receiving VKA therapy. PRIMARY FUNDING SOURCE Johnson & Johnson and Bayer HealthCare.