title: Trends in the prescription of novel oral anticoagulants in UK primary care.
abstract: OBJECTIVE
  Novel oral anticoagulants (NOACs) are alternatives to vitamin-K antagonists (VKAs) for the prevention of thromboembolism. It is unclear how NOACs have been adopted in the UK since first introduced in 2008. The present study was conducted to describe the trends in the prescription of NOACs in the UK, including dabigatran, rivaroxaban and apixaban.
  
  
  METHODS
  Using the UK's Clinical Practice Research Datalink, the rates of new use of NOACs and VKAs from 2009 to 2015 were calculated using Poisson regression. Patient characteristics associated with NOAC initiation were identified using multivariate logistic regression.
  
  
  RESULTS
  The overall rate of oral anticoagulant initiation increased by 58% over the study period [rate ratio (RR) 1.58; 95% confidence interval (CI) 1.23, 2.03], even as the rate of new VKA use decreased by 31% (RR 0.69; 95% CI 0.52, 0.93). By contrast, the rate of initiation of NOAC increased, particularly from 2012 onwards, with a 17-fold increase from 2012 to 2015 (RR 17.68; 95% CI 12.16, 25.71). In 2015, NOACs accounted for 56.5% of oral anticoagulant prescriptions, with rivaroxaban prescribed most frequently, followed by apixaban and then dabigatran. Compared to VKAs, new NOAC users were less likely to have congestive heart failure, coronary artery disease and peripheral vascular disease, and more likely to have a history of ischaemic stroke.
  
  
  CONCLUSIONS
  In the UK, the rate of initiation of NOACs has increased substantially since 2009, and these agents have now surpassed VKAs as the anticoagulant of choice. Moreover, the characteristics of patients initiated on NOACs have changed over time, and this should be accounted for in future studies comparing NOACs and VKAs.
authors.affiliation: Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, QC, Canada.|Centre for Clinical Epidemiology, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, QC, Canada.
authors.forename: Simone Y
authors.initials: SY
authors.lastname: Loo
authors.affiliation: Centre for Clinical Epidemiology, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, QC, Canada.
authors.forename: Sophie
authors.initials: S
authors.lastname: Dell'Aniello
authors.affiliation: INSERM, CIC 1410, Centre Hospitalier Universitaire de la Réunion, Saint-Pierre, France.
authors.forename: Laetitia
authors.initials: L
authors.lastname: Huiart
authors.affiliation: Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, QC, Canada.|Centre for Clinical Epidemiology, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, QC, Canada.|Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada.
authors.forename: Christel
authors.initials: C
authors.lastname: Renoux
mesh_terms: D000284:Administration, Oral; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000627:therapeutic use; D000069604:Dabigatran / Q000627:therapeutic use*; D004363:Drug Utilization / Q000706:statistics & numerical data / Q000639:trends*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D011320:Primary Health Care / Q000706:statistics & numerical data / Q000639:trends*; D011720:Pyrazoles / Q000627:therapeutic use*; D011728:Pyridones / Q000627:therapeutic use*; D000069552:Rivaroxaban / Q000627:therapeutic use*; D006113:United Kingdom; D014812:Vitamin K / Q000037:antagonists & inhibitors
chemical_list: D000925:Anticoagulants; D011720:Pyrazoles; D011728:Pyridones; D014812:Vitamin K; C522181:apixaban; D000069552:Rivaroxaban; D000069604:Dabigatran
keywords: atrial fibrillation; oral anticoagulants; pharmacoepidemiology; prescription patterns; venous thromboembolism