Systematic review with meta‐analysis: limited benefits from early colonoscopy in acute lower gastrointestinal bleeding
Bibliographic record
Abstract
BACKGROUND: The optimal timing of colonoscopy in acute lower gastrointestinal bleeding (LGIB) remains controversial. AIM: To characterise the utility of early colonoscopy (within 24 hours) in managing acute LGIB. METHODS: A systematic literature search to October 2019 identified fully published articles and abstracts of randomised controlled trials (RCTs) and observational studies with control groups assessing early colonoscopy in acute LGIB. The primary outcome was rebleeding. Secondary outcomes included mortality, surgery, length of stay (LOS), definite cause of bleeding and adverse events. Odds ratios (ORs) and mean differences (MD) were calculated. RESULTS: Of 1116 citations, 4 RCTs (466 patients) and 13 observational studies with elective colonoscopy (>24 hours) as control group (1 061 281 patients) were included. No differences in rebleeding were noted between early and elective colonoscopy groups among RCTs alone (OR = 1.70; 0.79; 3.64), or observational studies alone (OR = 1.20; 0.69; 2.09). No other significant between-group differences in outcomes were found when restricting the analysis to RCTs. Among observational studies only, early colonoscopy was associated with lower rates of all-cause mortality (OR = 0.86; 0.75; 0.98), surgery (OR = 0.52; 0.42; 0.64), blood transfusion (OR = 0.81; 0.75; 0.87), units of blood transfusion (MD = -4.30; -6.24; -2.36) and shorter LOS (MD = -1.70; -1.70; -1.70 days). CONCLUSION: In contradistinction to observational studies, data from RCTs do not support a role for early colonoscopy in the routine management of acute LGIB with regards to the most important clinical outcomes. Further research is needed to better identify patients with high-risk LGIB who may benefit from early colonoscopy.
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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 | 0.032 | 0.091 |
| Meta-epidemiology (narrow) | 0.004 | 0.002 |
| Meta-epidemiology (broad) | 0.023 | 0.054 |
| Bibliometrics | 0.007 | 0.007 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.005 | 0.003 |
| Open science | 0.003 | 0.002 |
| Research integrity | 0.003 | 0.003 |
| Insufficient payload (model declined to judge) | 0.006 | 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".