Drospirenone‐containing oral contraceptive pills and the risk of venous thromboembolism: a systematic review of observational studies
Bibliographic record
Abstract
BACKGROUND: The effects of fourth-generation drospirenone-containing combined oral contraceptives (COCs) on the risk of venous thromboembolism (VTE) are controversial. OBJECTIVES: To assess the methodological strengths and limitations of the evidence on the VTE risk of these COCs. SEARCH STRATEGY: We searched CINAHL, the Cochrane Library, EMBASE, HealthStar, Medline, and the Science Citation Index. SELECTION CRITERIA: Studies were included if they were cohort and case-control studies, reported a venous thrombotic outcome, had a comparator group, reported an effect measure of the association of interest, and were published in English or French. DATA COLLECTION AND ANALYSIS: We assessed study quality using the ROBINS-I tool and assessed the presence of four common sources of bias: prevalent user bias, inappropriate choice of comparator, VTE misclassification, and confounding. MAIN RESULTS: Our systematic review included 17 studies. The relative risks of VTE associated with drospirenone- versus second-generation levonorgestrel-containing COCs ranged from 1.0 to 3.3. Based on ROBINS-I, three studies had a moderate risk, ten had a serious risk, and four had a critical risk. Nine studies included prevalent users, four included inappropriate comparators, four had VTE misclassification, and five did not account for two or more important confounding factors. The three highest quality studies had relative risks ranging from 1.0 to 1.57. AUTHOR'S CONCLUSIONS: As a result of the methodological limitations of the individual studies, the VTE risk of drospirenone-containing COCs remains unknown. The highest quality studies suggest there are no or slightly increased harmful effects, but their confidence limits do not rule out an almost doubling of the risk. TWEETABLE ABSTRACT: Systematic review of drospirenone: best studies show no or slightly increased VTE risk (versus levonorgestrel).
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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 | 0.022 | 0.094 |
| Meta-epidemiology (narrow) | 0.001 | 0.002 |
| Meta-epidemiology (broad) | 0.008 | 0.010 |
| Bibliometrics | 0.014 | 0.016 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.003 | 0.002 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.002 | 0.001 |
| 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".