title: Evaluating the Initiation of Novel Oral Anticoagulants in Medicare Beneficiaries.
abstract: BACKGROUND
  As alternatives to warfarin, 2 novel oral anticoagulants (NOACs), dabigatran and rivaroxaban, were approved in 2010 and 2011 to prevent stroke and other thromboembolic events in patients with atrial fibrillation. It is unclear how patient characteristics are associated with the initiation of anticoagulants.
  
  
  OBJECTIVE
  To evaluate how patient demographics, clinical characteristics, types of insurance, and patient out-of-pocket spending affect the initiation of warfarin and 2 NOACs--dabigatran and rivaroxaban.
  
  
  METHODS
  We used pharmacy claims data from a 5% random sample of Medicare beneficiaries to identify patients who were newly diagnosed with atrial fibrillation between October 1, 2010, and October 31, 2012, and who were prescribed an oral anticoagulant within 60 days of diagnosis. We identified key predictors of initiation of NOACs using a multinomial logistic regression model with generalized logit link.
  
  
  RESULTS
  Patients who were black and who had a history of acute myocardial infarction, stroke or transient ischemic attack, chronic kidney disease, or congestive heart failure were significantly associated with lower odds of receiving NOACs compared with warfarin. Age greater than 65 years, a history of hypertension, and use of nonsteroidal anti-inflammatory drugs were positively associated with the initiation of NOACs. Rivaroxaban was most likely to be initiated among women, followed by warfarin and dabigatran. Individuals receiving a low-income subsidy were more likely to initiate warfarin than NOACs, even though they paid little copayment. Individuals with supplemental Part D drug coverage, such as national Programs for All-Inclusive Care for the Elderly or employer-sponsored plans, were more likely to initiate NOACs compared with warfarin.
  
  
  CONCLUSIONS
  We found that race, sex, type of Part D plans, and some clinical conditions were associated with the initiation of NOACs relative to warfarin. But patient demographic and clinical characteristics did not appear to affect which particular NOAC patients initiated.
authors.affiliation: 1 Staff Scientist, Lister Hill National Center for Biomedical Communications, National Library of Medicine, Bethesda, Maryland.
authors.forename: Seo Hyon
authors.initials: SH
authors.lastname: Baik
authors.affiliation: 2 PhD Student, Department of Health Policy and Management, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania.
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Hernandez
authors.affiliation: 3 Associate Professor and Director, Department of Health Policy and Management, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania.
authors.forename: Yuting
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000284:Administration, Oral; D000368:Aged; D000925:Anticoagulants / Q000191:economics* / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000517:prevention & control; D000069604:Dabigatran / Q000627:therapeutic use; D005260:Female; D005102:Health Expenditures; D006801:Humans; D007342:Insurance Benefits; D008297:Male; D006278:Medicare; D008875:Middle Aged; D000069552:Rivaroxaban / Q000627:therapeutic use; D020521:Stroke / Q000517:prevention & control; D014481:United States; D014859:Warfarin / Q000627:therapeutic use
chemical_list: D000925:Anticoagulants; D014859:Warfarin; D000069552:Rivaroxaban; D000069604:Dabigatran