In a study evaluating rivaroxaban (Xarelto; Bayer) versus warfarin for the treatment and prevention of recurrent venous thromboembolism (VTE) in patients with obesity, results favoured rivaroxaban at three, six, and 12 months.
First author Olivia S Costa (University of Connecticut School of Pharmacy, Storrs, USA and Hartford Hospital, Hartford, USA) recently presented study findings at the International Society on Thrombosis and Haemostasis (ISTH) 2020 virtual congress (12–14 July). The study had previously been published online on 25 June in the Journal of Thrombosis and Haemostasis.
Addressing the online audience, Costa concluded that, among patients with obesity experiencing an acute VTE, rivaroxaban was associated with a “significantly reduced risk” of recurrent VTE versus warfarin at three, six, and 12 months, without impacting major bleeding. She added that these findings remained consistent across evaluated body mass index (BMI) classes.
Costa noted that, while rivaroxaban has demonstrated consistent drug levels and anticoagulation activity in patients with obesity versus those of normal weight, limited data evaluating the effectiveness and safety of rivaroxaban versus warfarin in patients with obesity experiencing VTE exist.
In the present study, funded by Janssen, the investigators performed a cohort analysis using Optum de-identified electronic health record (EHR) data from 1 November 2012 to 30 September 2018. They included patients with a BMI ≥30kg/m2 admitted to the hospital, emergency department, or observation unit for VTE, who received rivaroxaban or warfarin as their first oral anticoagulant (OAC) within seven days after and had ≥12 months of EHR activity prior to the acute event. They excluded patients with evidence of OAC use at baseline.
Patients receiving rivaroxaban were 1:1 propensity-score matched to patients receiving warfarin. Costa noted that outcomes included recurrent VTE and major bleeding at three, six, and 12 months using an intent-to-treat approach. They also performed subanalyses stratified by BMI (30–34.9, 35–39.9, and ≥40kg/m2) and compared risk using Cox regression.
Costa et al identified 6,755 rivaroxaban and 6,755 warfarin users with a BMI ≥30kg/m2 experiencing an incident VTE. At three, six, and 12 months, rivaroxaban was associated with a reduced risk of recurrent VTE compared to warfarin. There was no difference in major bleeding observed between rivaroxaban and warfarin at three, six, and 12 months.
Furthermore, subanalyses did not show a statistically significant interaction across BMI categories for either the recurrent VTE (p-interaction≥0.43) or major bleeding (p-interaction≥0.58) outcomes at any time point.