Title of Research: Effectiveness and safety of extended anticoagulation for venous thromboembolism
Additional Authors: W. Lo-Ciganic; C. DeRemer; E. Dietrich; P. Huang; H. Park
Due to limited real-world evidence for effectiveness and safety of extended anticoagulation beyond 6-month initial treatment for venous thromboembolism (VTE), we aimed to assess the extended use of apixaban or warfarin for prevention of recurrent VTE and major bleeding (MB) in VTE patients. A retrospective cohort study using 2013-2019 Truven Commercial and Medicare Supplemental database was conducted in patients aged ≥18 years with an inpatient VTE diagnosis. Patients were included if they initiated anticoagulants within 30 days of their first VTE, completed 6-month initial therapy, and had extended treatment of either apixaban or warfarin or no extended therapy. Study outcomes including VTE and MB were measured until the occurrence of the first outcome, switch to the comparator, end of study period, or end of enrollment. Multivariable Cox proportional hazards modeling with inverse probability treatment weighting was used to obtain adjusted hazard ratio (aHR) and 95% confidence interval (95%CI). The study cohort (age=60±15 years and 50% males) consisted of 4,338 apixaban users, 5,298 warfarin users, and 5,182 untreated patients. Compared to no treatment, apixaban was associated with a decreased risk of recurrent VTE (aHR=0.11, 95%CI=0.03-0.25) without increasing the risk of MB (aHR=0.92, 95%CI=0.45-1.91); warfarin was associated with a decreased risk of recurrent VTE (aHR=0.22, 95%CI=0.11-0.43) but with an increased MB risk (aHR=2.53, 95%CI=1.46-4.38). Compared to warfarin, apixaban was associated with a lower risk of MB (aHR=0.39, 95%CI=0.20-0.76) without a difference in recurrent VTE risk (aHR=0.45, 95% CI=0.15-1.33). Therefore, our findings suggest apixaban as an effective and safer option for extended treatment of VTE when compared to warfarin or no treatment.
About the author
Hyerim Kang, Ph.D., is a Post-Doctoral associate in the Department of Pharmaceutical Outcomes and Policy. She received her PharmD and Ph.D. at the Sungkyunkwan University of South Korea, School of Pharmacy, Pharmaceutical Policy & Outcomes Research. Her research centers on the health outcomes studies of medications as well as the cost-effectiveness of new medications. She is enthusiastic about investigating questions associated with the safety and clinical effectiveness of pharmaceuticals and, particularly, how a medication affects the health outcomes in real-world clinical care settings.