Effectiveness and safety of rivaroxaban versus warfarin for treatment and prevention of recurrence of venous thromboembolism

The efficacy and safety or rivaroxaban versus enoxaparin/vitamin K antagonist for treatment and prevention recurrence of venous thromboembolism (VTE) was demonstrated in the randomised EINSTEIN trials. We assessed the effectiveness and safety of rivaroxaban versus warfarin in VTE patients managed in routine practice. Using US MarketScan claims from 1/2012-6/2015, we included adults with a primary diagnosis of deep vein thrombosis (DVT) or pulmonary embolism (PE) during a hospitalisation/emergency department visit, newly-initiated on rivaroxaban or warfarin within 30-days after the VTE and with ≥180-days of continuous medical/prescription benefits prior to the VTE (baseline). Patients with a claim for anticoagulation at baseline were excluded. Recurrent VTE, major bleeding, intracranial haemorrhage (ICH) and gastrointestinal bleeding (GIB) were assessed. Differences in baseline characteristics between cohorts were adjusted for using inverse probability of treatment weights based on propensity-scores. Patients had a maximum of 12-months period of follow-up post-VTE or until endpoint occurrence, switch/discontinuation of index anticoagulation, insurance disenrollment or end-of-follow-up. Cox regression was performed and reported as hazard ratios (HRs) with 95 % confidence intervals (CIs). In total, 13,609 rivaroxaban and 32,244 warfarin users experiencing VTE were included. Rivaroxaban was associated with an 19 % (95 %CI=10-27 %) reduction in recurrent VTE and a 21 % (95 %CI=4-35 %) reduction in major bleeding hazard versus warfarin. Rivaroxaban was also associated with significantly decreased hazards of ICH (HR=0.40) and GIB (HR=0.72). Rivaroxaban appears to reduce patients' hazard of both recurrent VTE and major bleeding in routine practice. These results appear consistent with EINSTEIN and post-marketing registry studies.