Abstract P6: Vitamin K Antagonist Dosing Methods and Individual Patient Quality of INR Control in the International Active W Anticoagulation Study
Bibliographic record
Abstract
Background The net benefit of vitamin K antagonists (VKAs) depends on the time spent in the therapeutic range (TTR) for the International Normalized Ratio in individual patients. Evidence-based methods are recommended by guidelines. We assessed VKA dosing methods among ACTIVE W study sites and the association with TTR in individual atrial fibrillation patients. Methods ACTIVE W sites received a survey questionnaire after the study to assess VKA dosing methods. Univariable and multivariable linear mixed models, to account for the random effect of clinic-level survey data, were used to assess the association of dosing methods with patient TTR. Patient-level covariates in multivariable analysis were: age, sex, CHADS 2 stroke risk score, mini-mental state examination score, history of VKA use, VKA type, and use of aspirin, amiodarone and insulin. Results The questionnaire was returned by 333 of 493 ACTIVE W sites (68%) who had at least one patient randomized to VKA. Responding sites had a higher mean study TTR than non-responding sites (64 vs. 60%; p=0.0101) and were mainly specialized in cardiology (87%). Only 28% of sites managed VKA dosing with an evidence-based method: an anticoagulation clinic, computer dosing system or patient self-management. Also taking in account (non-validated) manual algorithms, 64% of sites managed VKA dosing primarily based on clinical experience. In univariable analysis, patients achieved a higher TTR when managed by an anticoagulation clinic vs. by the study physician (67.3 vs. 62.1%; p=0.0027), when managed using a computer dosing system vs. using clinical experience (72.9 vs. 63.6%; p=0.0026), and when managed using at least one evidence-based method vs. not using evidence-based methods (67.3 vs. 62.8%; p=0.0045). However, when adding patient data in multivariable analysis, these three associations became non-significant (p-values 0.4659, 0.6555 and 0.6058, respectively). Conclusion The use of evidence-based VKA dosing methods was reported by only 28% of ACTIVE W sites, but was not significantly associated with an improved TTR when accounting for patient characteristics.
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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 | 0.005 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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".