Trends in Prescribing Oral Anticoagulants in Canada, 2008–2014
Bibliographic record
Abstract
PURPOSE: The non-vitamin K antagonist oral anticoagulants (NOACs), dabigatran, rivaroxaban, and apixaban, provide several advantages over vitamin K antagonists, such as warfarin. Little is known about the trends of prescribing OACs in Canada. In this study we analyzed changes in prescription volumes for OAC drugs since the introduction of the NOACs in Canada overall, by province and by physician specialty. METHODS: Canadian prescription volumes for warfarin, dabigatran, rivaroxaban, and apixaban from January 2008 to June 2014 were obtained from the Canadian Compuscript Audit of IMS Health Canada Inc and were analyzed by physician specialty at the national and provincial levels. Total prescriptions by indication were calculated based on data from the Canadian Disease and Therapeutic Index for all OAC indications and for each commonly prescribed dose of dabigatran (75, 110, and 150 mg), rivaroxaban (10, 15, and 20 mg), and apixaban (2.5 and 5 mg). FINDINGS: The overall number of OAC prescriptions in Canada has increased annually since 2008. With the availability of the NOACs, the proportion of total OAC prescriptions attributable to warfarin has steadily decreased, from 99% in 2010 to 67% by June 2014, and the absolute number of warfarin prescriptions has been decreasing since February 2011. The greatest decline in proportionate warfarin prescriptions was in Ontario. In general, the increase of NOAC prescriptions coincided with the introduction of provinces' reimbursement of NOAC prescription costs. The proportion of total OAC prescriptions represented by the NOACs varied by specialty, with the greatest proportionate prescribing found among orthopedic surgeons, cardiologists, and neurologists. IMPLICATIONS: Since their approval, the NOACs have represented a growing share of total OAC prescriptions in Canada. This trend is expected to continue because the NOACs are given preference over warfarin in guidelines on stroke prevention in patients with atrial fibrillation, because of growing physician experience, and due to the emergence of potential new indications. An understanding of the current prescribing patterns will help to encourage knowledge translation and possibly influence policy/reimbursement strategies.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.005 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.004 | 0.011 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".