Duration of primary/secondary treatment to prevent recurrent venous thromboembolism: a systematic review and meta-analysis
Bibliographic record
Abstract
ABSTRACT: Antithrombotic therapy can prevent recurrent deep vein thrombosis (DVT) and pulmonary embolism (PE). It is, however, associated with an increased risk for major bleeding. This meta-analysis systematically reviewed the evidence regarding the duration of antithrombotic therapy to assess benefits and harms. We systematically searched for randomized controlled trials (RCTs) that compared shorter (3-6 months) with longer (>6 months) courses of anticoagulation for the primary treatment of venous thromboembolism (VTE) or that compared discontinued with indefinite antithrombotic therapy for the secondary prevention of VTE. Pairs of reviewers screened the eligible trials and collected data. This study included 22 RCTs (11 617 participants). Pooled estimates showed that, for the primary treatment of unprovoked VTE, VTE provoked by chronic risk factors or transient risk factors, treating patients with a longer course (>6 months) of anticoagulation, as opposed to a shorter course (3-6 months), probably reduced recurrent PE (risk ratio [RR], 0.66; 95% confidence interval [CI], 0.42-1.02) and DVT (RR, 0.85; 95% CI, 0.63-1.14), but it was associated with increased mortality (RR, 1.43; 95% CI, 0.85-2.41) (moderate certainty) and a higher risk for major bleeding (RR, 2.02; 95% CI, 1.02-3.98; high certainty). For the secondary prevention of unprovoked VTE and VTE provoked by chronic risk factors, when compared with discontinuing treatment, indefinite anticoagulation therapy was associated with decreased mortality (RR, 0.54; 95% CI, 0.36-0.81), a reduction in recurrent PE (RR, 0.25; 95% CI, 0.16-0.41) and DVT (RR, 0.15; 95% CI, 0.10-0.21), and an increase in the risk for bleeding (RR, 1.98; 95% CI, 1.18-3.30), all supported by high certainty. Indefinite antiplatelet therapy may be associated with decreased mortality (RR, 0.95; 95% CI: 0.53-1.68; low certainty), probably a reduction in recurrent PE (RR, 0.65; 95% CI, 0.41-1.03) and DVT (RR, 0.44; 95% CI, 0.17-1.13) (moderate certainty), and may increase the risk for bleeding (RR, 1.28; 95% CI, 0.48-3.41; low certainty). In summary, for the primary treatment of all types of VTE, shorter (3-6 months) duration of anticoagulation is more beneficial. For the secondary prevention of unprovoked VTE or VTE provoked by chronic risk factors, indefinite antithrombotic treatment is more beneficial.
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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 | 0.012 | 0.028 |
| Meta-epidemiology (narrow) | 0.003 | 0.002 |
| Meta-epidemiology (broad) | 0.021 | 0.041 |
| Bibliometrics | 0.005 | 0.006 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.003 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.005 | 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".