title: Warfarin Discontinuation in Patients With Unprovoked Venous Thromboembolism: A Large US Insurance Database Analysis.
abstract: This study examined warfarin therapy discontinuation and its risk factors among patients with unprovoked venous thromboembolism (VTE) in the US clinical practice setting. Adult patients with unprovoked VTE were identified from the MarketScan claims database from January 1, 2006 to December 31, 2012. The index date was defined as the date of first VTE diagnosis. Patients were required to have no VTE diagnosis in the 6 months before index date and continuous health plan enrollment for 6 months before and 12 months after the index date. Warfarin discontinuation rates and adjusted hazard ratios (HRs) were reported. Of 21,163 eligible patients, 15,463 were diagnosed with deep vein thrombosis (DVT) only (73.1%), 5027 with pulmonary embolism (PE) only (23.7%), and 673 with DVT and PE (3.2%). The average duration of warfarin therapy was 5.2 months (SD = 3.0). During 1-year follow-up, 21.4% patients discontinued therapy within 3 months, 42.8% within 6 months, and 70.1% within 12 months. PE versus DVT [HR = 0.77, 95% confidence interval (CI) = 0.74-0.80], comorbid atrial fibrillation (HR = 0.73, 95% CI = 0.66-0.81), thrombophilia (HR = 0.62, 95% CI = 0.54-0.71), and age >40 years (41-65 years: HR = 0.86, 95% CI = 0.81-0.91; >65 years: HR = 0.82, 95% CI = 0.77-0.87) were significantly associated with reduced risk of warfarin discontinuation. Alcohol abuse/dependence (HR = 1.36, 95% CI = 1.20-1.55), cancer history (HR = 1.13, 95% CI = 1.07-1.19), bleeding (HR = 1.07, 95% CI = 1.01-1.15), and catheter ablation (HR = 1.10, 95% CI = 1.00-1.20) in the 6 months before index date were significantly associated with increased risk for warfarin discontinuation. In conclusion, nearly 1 of 4 patients with unprovoked VTE discontinued warfarin within 3 months. Three of 4 patients discontinued therapy within 1 year. Younger age and multiple clinical factors are associated with warfarin therapy discontinuation.
authors.affiliation: 1STATinMED Research, Ann Arbor, MI; 2Pfizer Inc, New York, NY; 3University of Tennessee College of Pharmacy, Memphis, TN; 4Bristol-Myers Squibb Inc, Princeton, NJ; 5Columbia University, New York, NY; 6STATinMED Research, New York, NY; and 7MEF University, Istanbul, Turkey.
authors.forename: Lin
authors.initials: L
authors.lastname: Xie
authors.forename: Xianchen
authors.initials: X
authors.lastname: Liu
authors.forename: Hemant
authors.initials: H
authors.lastname: Phatak
authors.forename: Jack
authors.initials: J
authors.lastname: Mardekian
authors.forename: Wilson
authors.initials: W
authors.lastname: Tan
authors.forename: Onur
authors.initials: O
authors.lastname: Baser
authors.forename: Eduardo
authors.initials: E
authors.lastname: Ramacciotti
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage* / Q000009:adverse effects; D001281:Atrial Fibrillation / Q000188:drug therapy; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D005500:Follow-Up Studies; D006470:Hemorrhage / Q000139:chemically induced / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000188:drug therapy / Q000473:pathology; D012189:Retrospective Studies; D012307:Risk Factors; D014481:United States; D054556:Venous Thromboembolism / Q000188:drug therapy* / Q000473:pathology; D020246:Venous Thrombosis / Q000188:drug therapy / Q000473:pathology; D014859:Warfarin / Q000008:administration & dosage* / Q000009:adverse effects; D055815:Young Adult; D016903:Drug Monitoring
chemical_list: D000925:Anticoagulants; D014859:Warfarin