Effect of B-vitamins on stroke risk among individuals with vascular disease who are not on antiplatelets: A meta-analysis
Bibliographic record
Abstract
BACKGROUND: Retrospective analyses of randomized controlled trials suggest that antiplatelet therapy may modify the potential cerebrovascular benefits of lowering homocysteine with B-vitamins among individuals with cardiovascular disease. We evaluated the effects of B-vitamin supplementation on risk of subsequent stroke among high cardiovascular risk individuals who are not taking antiplatelet medications. METHODS: We systematically searched the Cochrane Central Register of controlled trials, PubMed, the Internet Stroke Center stroke trials, and the clinical trials.gov website from 1966 to April 2015. Inclusion criteria included: randomized controlled trials of homocysteine-lowering therapy with B-vitamins; high cardiovascular risk population and follow-up ≥1 year. We considered stroke as the primary outcome. Among 11 randomized controlled trials meeting inclusion criteria, three studies assessed stroke as an outcome and reported event rates according to whether or not individuals were taking antiplatelets: Vitamin Intervention for Stroke Prevention (VISP), VITAmins TO Prevent Stroke (VITATOPS), and Heart Outcomes Prevention Evaluation 2 (HOPE-2). RESULTS: A total of 4643 high vascular risk subjects not taking antiplatelets were evaluated. The overall effect size across studies was summarized using the fixed effects model after confirming there was no significant heterogeneity. Heterogeneity was assessed using the Cochran's Q and I(2) statistics. Compared with the control group, those taking B-vitamin supplementation had a lower risk of recurrent stroke (HR 0.86, 95% CI 0.62 to 1.19 for VISP; 0.65, 0.46 to 0.91 for VITATOPS; and 0.60, 0.39 to 0.92 for HOPE-2; overall HR 0.71, 0.58 to 0.88). CONCLUSION: Homocysteine lowering with B-vitamins among high vascular risk patients who are not taking antiplatelet therapy is related to a significant reduction (29%) in overall stroke risk. A clinical trial of B-vitamins in this group may be warranted.
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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 | 0.021 | 0.039 |
| Meta-epidemiology (narrow) | 0.004 | 0.002 |
| Meta-epidemiology (broad) | 0.027 | 0.084 |
| Bibliometrics | 0.008 | 0.007 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.005 | 0.002 |
| Open science | 0.003 | 0.002 |
| Research integrity | 0.003 | 0.003 |
| Insufficient payload (model declined to judge) | 0.003 | 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".