Prescribing patterns of novel oral anticoagulants following regulatory approval for atrial fibrillation in Ontario, Canada: a population-based descriptive analysis
Bibliographic record
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). INTERPRETATION: 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.
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.008 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".