Results from a new real-world study evaluating rivaroxaban (Xarelto; Janssen), a factor Xa inhibitor, in morbidly obese patients were recently published in Thrombosis Research.
The retrospective cohort study analyzed data from 2 US claims databases (Truven MarketScan Commercial Claims and Encounters database and MarketScan Medicare Supplemental database) to evaluate the clinical and health/economic outcomes of rivaroxaban vs warfarin for venous thromboembolism (VTE) in morbidly obese patients (N=5722). The study included adult patients with ≥1 medical claim with a VTE diagnosis from December 1, 2012 to September 30, 2016, and required rivaroxaban or warfarin treatment to be initiated within 28 days of VTE diagnosis and ≥1 diagnosis of morbid obesity.
Two analyses were conducted: an intent-to-treat (ITT) analysis (N=2890 matched pairs) that included patients who were followed until the first event of interest or until the end of the 12-month observation period and an on-treatment analysis (N=2832 matched pairs) where patients were followed from treatment initiation to discontinuation. The primary outcome was the risk of recurrent VTE, defined as a hospitalization (inpatient service) or emergency room (ER) visit with a primary diagnosis of VTE during the follow-up period; secondary outcomes included major bleeding risk, healthcare resource utilization (HRU), and costs.
Results for the ITT analysis did not show a significant difference for the risk of recurrent VTE with rivaroxaban, 16.8%, compared with warfarin, 15.9% (Odds Ratio [OR]: 0.99; 95% CI: 0.85, 1.14; P =.8443). However, rivaroxaban treatment resulted in significantly fewer major bleeding events vs warfarin (1.8% vs 2.5%, respectively; OR:0.66; 95% CI: 0.45, 0.98; P =.0388).
Moreover, rivaroxaban was associated with a significantly lower HRU vs warfarin, including fewer hospitalizations (35.1% vs 38.6% of patients, respectively; OR: 0.86; 95% CI: 0.77, 0.96; P =.0057) and 19 fewer per patient per year outpatient visits, including laboratory visits (P <.0001). In addition, average total medical costs per patient per year were significantly lower with rivaroxaban treatment vs warfarin ($34,824 vs $37,653, respectively; P =.0201).
The on-treatment analysis did not show significant differences for recurrent VTE and major bleeding between rivaroxaban and warfarin; rivaroxaban was associated with significantly lower all-cause HRU and overall medical costs compared with warfarin.
“This is the first large-scale, real-world study to evaluate a direct oral anticoagulant (DOAC) in morbidly obese patients with VTE, and the first to identify healthcare resource utilization and medical costs in this population,” said Alex C. Spyropoulos, MD, Professor of Medicine, The Donald and Barbara Zucker School of Medicine, Hofstra University, Northwell Health at Lenox Hill Hospital, New York, NY. “We now know from this research that rivaroxaban is as effective and safe as dose-adjusted warfarin when treating morbidly obese patients, without the need for routine anti-Xa measurements, and with significantly lower healthcare resource utilization.”
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