(226) Risk of Second Recurrent Venous Thromboembolism and Major Bleeding Events Among Patients with Extended Anticoagulant Treatment: A Retrospective Cohort Study

Saturday, August 27, 2022

8:00 AM – 6:00 PM CEST

Location: Hall C

Publication Number: 900

Presenting Author(s)

Haesuk Park
– University of Florida, University of Florida, Gainesville, Florida, United States

Co-Author(s)

Hye-Rim Kang
– Department of Pharmaceutical Outcomes and Policy, College of Pharmacy, University of Florida, GAINESVILLE, FL, United States
Pei-Lin Huang, MHS
– Department of Pharmaceutical Outcomes and Policy, College of Pharmacy, University of Florida, United States
Eric A. Dietrich, PharmD
– Department of Pharmacotherapy and Translational Research, College of Pharmacy, University of Florida, United States
Christina E. DeRemer, PharmD
– Department of Pharmacotherapy and Translational Research, College of Pharmacy, University of Florida, United States
Weihsuan Jenny Lo-Ciganic, PhD
– Associate Professor, University of Florida Department of Pharmaceutical Outcomes and Policy, Gainesville, Florida, United States

Background: Limited real-world evidence exists for whether extended oral anticoagulation offers benefits over risks among patients with venous thromboembolism (VTE) who experience recurrent VTE following their initial anticoagulant therapy.

Objectives: To assess the effectiveness and safety of extended use of direct-acting oral anticoagulants (DOACs) compared with warfarin for preventing the second recurrent VTE and adverse major bleeding events among patients who had the first recurrent VTE within 12 months after they were started on their initial oral anticoagulant therapy for the first VTE.

Methods: We conducted a retrospective cohort study using two data sources: (1) MarketScan Commercial and Medicare Supplemental database (2013-2019) and (2) Medicare claims database (2014-2018). We included patients aged ≥18 years with a diagnosis of deep vein thrombosis or pulmonary embolism ascertained from inpatient claims. We included patients who initiated any oral anticoagulants within 30 days after the first VTE, experienced the first recurrent VTE within 12 months following anticoagulant initiation, and had extended treatment with either DOAC (apixaban or rivaroxaban) or warfarin within 30 days of the first recurrent VTE. The study outcomes were time to the second recurrent VTE and major bleeding events. We censored patients when they had a switch to the comparator, discontinuation (> 7-day gap between anticoagulant refills), end of enrollment, or end of study period, whichever occurred first. We used Cox proportional hazards modeling with inverse probability treatment weighting to obtain hazard ratio (HR) and 95% confidence interval (95% CI) for DOAC users compared with warfarin users.

Results: The study cohort (mean age=63 ±16 years; 56% females) consisted of 863 DOAC users and 596 warfarin users. The incidence rates of second recurrent VTE were 2.97 and 7.68 per 100 person-years, and those of major bleeding were 2.98 and 5.09 per 100 person-years in the DOAC and warfarin groups, respectively. Compared with warfarin users, DOAC users were associated with a decreased risk of second recurrent VTE (HR=0.38, 95% CI=0.18-0.77) without an increased major bleeding risk (HR=0.57, 95% CI=0.26-1.26). Results from subgroup analyses by age (≥65 vs < 65), sex, and type of first recurrent VTE (PE vs DVT, provoked vs unprovoked), HAS-BLED score (≥3 vs < 3), chronic kidney disease, and cancer remained consistent with the main findings.

Conclusions: Extended anticoagulation with DOAC was associated with a reduced risk of second recurrent VTE without increased major bleeding risk among patients who experienced a first episode of recurrent VTE following the initial anticoagulant therapy compared with warfarin.