Apixaban Versus Dalteparin for Thromboprophylaxis in Patients with Acute Spinal Cord Injury: A Pilot Study
Bibliographic record
Abstract
Background: Patients with acute spinal cord injury (SCI) have a high risk of venous thromboembolism despite thromboprophylaxis. Low molecular weight heparin (LMWH), the current standard of care, is inconvenient for long term thromboprophylaxis, costly, and partially effective. Direct oral anticoagulants (DOACs) have been shown to be at least as effective and as safe as LMWH in other thromboprophylaxis settings but there is no randomized evaluation of DOACs in this population. Aim: By conducting a feasibility randomized trial, we aimed to determine the likely recruitment rate of eligible patients into an RCT in which patients with acute SCI were randomized to a prophylactic dose of LMWH or apixaban. Methods: A pilot study was performed at Hamilton General Hospital (HGH). Adult patients with an acute traumatic SCI presenting to the hospital within 1 week of SCI and at least 36 h after the injury were included. Exclusion criteria were the need for therapeutic oral anticoagulation prior to enrolment; active bleeding, intracranial or peri-spinal hematoma, or a bleeding disorder; pregnancy or breastfeeding; severe renal failure (creatinine clearance ≤30 ml/min); severe cirrhosis (Child-Pugh class C); severe thrombocytopenia (platelets <50), unsuitability as determined by the attending physician; geographic inaccessibility; failure to obtain written consent; previous hypersensitivity to study drugs; or expected short hospital admission (≤7 days) due to a minor injury. Eligible patients were randomized to apixaban 2.5 mg twice daily or dalteparin 5000 units once daily for 90 days or until fully mobilized, whatever came first. The primary feasibility outcome was recruitment rate per year. We expected a recruitment rate of 20 patients per year based on an estimated admission rate in a retrospective study at HGH. The primary efficacy outcome was a composite of symptomatic, objectively verified, venous thromboembolism (upper or lower limb deep vein thrombosis (DVT) and/or pulmonary embolism (PE)) or sudden death where PE cannot be excluded. This outcome did not include a catheter-associated DVT. The primary safety end-point was major bleeding. Results: A total of 26 eligible patients were screened and 8 patients were enrolled per year resulting in a recruitment yield of 30.8% (95% confidence interval: 16-50%). The reasons for exclusion included: presence of an epidural hemorrhage (n=8), failure to obtain consent (n=2), not suitable for the study (n=2), >1 week from SCI (n=2), indication for therapeutic anticoagulation (n=2), active bleeding (n=1), and minor injury with an expected short hospital admission (n=1). Four patients were randomized to each drug. Median age was 61 (range 51 to 70) and 7 (87.5%) were males. There were no symptomatic VTE or sudden deaths. One patient randomized to apixaban had major bleeding. There were no serious adverse events. Conclusions: Our pilot study is the first randomized trial to examine the role of a DOAC compared with LMWH for thromboprophylaxis in this high-risk group. The primary feasibility outcome was not met, and therefore a multicenter RCT is unlikely to be feasible. The efficacy and safety of DOACs on this indication should be evaluated in registry- or health care database studies. Disclosures Eikelboom: Heart and Stroke Foundation: Research Funding; Sanofi Aventis: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Glaxo Smith Kline: Honoraria, Research Funding; Eli Lilly: Honoraria, Research Funding; Daiichi Sankyo: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; Boehringer Ingelheim: Honoraria, Research Funding; Bayer: Honoraria, Research Funding; AstraZeneca: Honoraria, Research Funding.
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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 | 0.005 | 0.007 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.004 | 0.004 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.003 |
| Insufficient payload (model declined to judge) | 0.010 | 0.001 |
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".