title: Prescribing patterns of novel oral anticoagulants following regulatory approval for atrial fibrillation in Ontario, Canada: a population-based descriptive analysis.
abstract: BACKGROUND
  The clinical armamentarium for anticoagulation has expanded substantially since the recent approval of dabigatran, rivaroxaban and apixaban for the prevention of stroke in atrial fibrillation. However, patients in the general population often differ from participants in clinical trials. In this study, we assessed the uptake of these novel oral anticoagulants in Ontario, Canada, within the first 2 years after dabigatran's approval for this indication.
  
  
  METHODS
  Using data on province-wide prescription volumes, we conducted a time-series analysis of prescription trends between October 2010 and September 2012 for all orally administered anticoagulants (warfarin, dabigatran and rivaroxaban) that were available in this period. We stratified dabigatran prescription rates by age group (20-39, 40-59, 60-64, 65-84 and ≥ 85 yr). We compared the proportion of dabigatran prescriptions to patients aged 65 or older with similar data from the Randomized Evaluation of Long-Term Anticoagulation Therapy (RE-LY) study.
  
  
  RESULTS
  Over the 24-month study period, we found that prescriptions for the novel anticoagulants rose more than 20-fold, to represent 21.1% of all prescriptions of oral anticoagulants by September 2012. The rise in prescriptions was due primarily to an increase in dabigatran use. Prescription rates of dabigatran were highest among people aged 85 years or more, a group at increased risk of bleeding who are markedly older than the average participant in the clinical trial in which the drug was tested (71 yr). In September 2012, most of the dabigatran prescriptions were for the lower-dose formulation (110 mg) in the older groups (58.8% of dabigatran prescriptions in the 65-84 age group and 93.6% in the oldest group).
  
  
  CONCLUSIONS
  We observed rapid growth in the uptake of the novel oral anticoagulants since their approval for use in patients with atrial fibrillation, especially among those aged 85 years or more. This increase in use in the oldest group, a population at high risk of bleeding, signals the need to evaluate outcomes of use of novel oral anticoagulants in the clinical setting.
authors: The School of Medicine, Division of Cardiology, Queen's University, Kingston, Ont.
authors: Yan
authors: Y
authors: Xu
authors: The Division of Clinical Pharmacology and Therapeutics, Department of Medicine, McMaster University, Hamilton, Ont.
authors: Anne M
authors: AM
authors: Holbrook
authors: The Department of Medicine, Queen's University, Kingston, Ont.
authors: Christopher S
authors: CS
authors: Simpson
authors: The Division of Neurology, Department of Medicine, and the Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ont.
authors: Dar
authors: D
authors: Dowlatshahi
authors: The Department of Population Health Sciences, Queen's University, Kingston, Ont.;
authors: Ana P
authors: AP
authors: Johnson