Rivaroxaban for thromboprophylaxis after orthopaedic surgery: Pooled analysis of two studies
Bibliographic record
Abstract
Rivaroxaban (BAY 59-7939) is an oral, direct factor Xa inhibitor in clinical development for the prevention and treatment of venous thromboembolism (VTE). This analysis of pooled results from two phase II studies of rivaroxaban for VTE prevention after major orthopaedic surgery aimed to strengthen the conclusions of the individual studies. One study was conducted in patients undergoing total hip replacement (THR; N = 722), and one in patients undergoing total knee replacement (TKR; N = 621). In both studies, patients were randomized, doubleblind, to oral, twice-daily (bid) rivaroxaban beginning after surgery, or subcutaneous enoxaparin (40 mg once daily beginning before THR, and 30 mg bid beginning after TKR). Treatment continued until mandatory bilateral venography was performed 5-9 days after surgery. Total VTE (deep vein thrombosis, pulmonary embolism, and all-cause mortality) occurred in 16.1-24.4% of per-protocol patients receiving rivaroxaban 5-60 mg, and 27.8% receiving enoxaparin (n = 914). There was a flat dose response relationship between rivaroxaban and total VTE (p = 0.39). Major bleeding (safety population, n = 1,317) increased dose-dependently with rivaroxaban (p < 0.001), occurring in 0.9%, 1.3%, 2.1%, 3.9%, and 7.0% of patients receiving rivaroxaban total daily doses of 5, 10, 20, 40, and 60 mg, respectively, versus 1.7% of patients receiving enoxaparin. No routine coagulation monitoring was performed, and there were no significant differences between dose response relationships with rivaroxaban after THR and TKR. Overall, rivaroxaban total daily doses of 5-20 mg had the most favorable balance of efficacy and safety, relative to enoxaparin, for the prevention of VTE after major orthopaedic surgery.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.001 | 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".