Abstract 12664: Persistence on Warfarin Therapy in Patients with Venous Thromboembolism: A Large US Insurance Database Analysis
Introduction: Adherence to antithrombotic therapy is crucial to prevent recurrence of venous thromboembolism (VTE). This study examined persistence on warfarin therapy among VTE patients in the US clinical practice setting.
Methods: We identified adult VTE patients from the Truven Health MarketScan insurance database. Index date was defined as the first VTE diagnosis between 07/01/2006 - 12/31/2011. Patients were required to have ≥2 VTE outpatient diagnosis claims within a 3-week window, have continuous health plan enrollment for 6 months prior to the index date, and have no VTE diagnosis in the 6 months prior. Warfarin was considered discontinued if a patient did not have a prescription refilled within 45 days after the ending date of last prescription. Persistence was defined as duration on warfarin from initiation to discontinuation. We reported discontinuation rates of warfarin therapy and adjusted hazard ratios (HRs) via Cox regression.
Results: Of 153,809 eligible patients, 119,988 were with deep vein thrombosis (DVT) only (78.0%), 30,048 with pulmonary embolism (PE) only (19.5%); and 3,773 with both (2.5%). Within 10 days of index diagnosis, 70,192 (45.6%) were treated with warfarin and 39,719 (56.6%) of those patients had ≥ 1 year follow-up. Average therapy duration on warfarin was 5.0 months and 74.8% discontinued therapy within 1 year. Patients aged >40 years (HR=0.87) and patients with PE vs. DVT (HR=0.76), atrial fibrillation (HR=0.75), and thrombophilia (HR=0.66) were less likely to discontinue warfarin therapy (p≤.05). Patients with history of pregnancy (HR=1.35), fracture (HR=1.24), alcohol/drug abuse (HR=1.17), hormone therapy (HR=1.13), and major bleeding (HR=1.09) in the 6 months prior were significantly at risk for warfarin discontinuation (p≤.05).
Conclusions: Less than half of patients in the US clinical practice setting started warfarin therapy within 10 days of incident VTE and most patients discontinued therapy within one year. PE patients and those with comorbid atrial fibrillation and thrombophilia were less likely to discontinue warfarin therapy, while those with history of bleeding, pregnancy, fracture, alcohol/drug abuse, and hormone therapy were at risk of discontinuation.
- © 2013 by American Heart Association, Inc.