Time in therapeutic range and stability over time for warfarin users in clinical practice: a retrospective cohort study using linked routinely collected health data in Alberta, Canada
Bibliographic record
Abstract
OBJECTIVES: Whether warfarin-treated patients with non-valvular atrial fibrillation (NVAF) who exhibit good control will experience deterioration in control over time is uncertain. We designed this study to examine the time in therapeutic range (TTR) in a population-based cohort of patients with NVAF recently initiated on warfarin. DESIGN: Retrospective cohort study using routinely collected health data from 2008 to 2015. SETTING: The Canadian province of Alberta. PARTICIPANTS: All adults with NVAF who were taking warfarin for >1 month. MAIN OUTCOME MEASURES: Frequency of international normalised ratio (INR) monitoring and the Rosendaal TTR with time zero set at 31 days after the first warfarin dispensation. RESULTS: 65%); good control continued to be exhibited by 8177 (57.1% of those who remained on warfarin) during months 7-12 and 6804 (56.8% of continuing warfarin users) in months 13-18. Good control in the first 6 months predicted good control over the subsequent year: adjusted OR (aOR) 4.0(95%CI 3.8 to 4.2), c index 0.685(95%CI 0.679 to 0.691) for months 7-12 and aOR 3.2(95%CI 3.1 to 3.3), c index 0.665(95%CI 0.659 to 0.671) for months 13-18. CONCLUSIONS: Nearly one-third of warfarin-treated patients had insufficient INR monitoring-this could influence the initial choice of anticoagulant and identifies a target for future quality improvement efforts. Of those warfarin-treated patients who went for regular INR monitoring, 41% exhibited levels of control similar to that in randomised trials and this deteriorated by half over time. However, in patients who have already exhibited adherence with regular monitoring and good TTR, warfarin may still be a reliable anticoagulation option.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.007 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".