Assessing heterogeneity in meta‐analyses of <i>Helicobacter pylori</i> infection‐related clinical studies: a critical appraisal
Bibliographic record
Abstract
OBJECTIVE: To critically assess the meta-analyses of Helicobacter pylori infection-related clinical studies, particularly the handling of between-study heterogeneity. METHODS: A qualitative, all-language, systematic literature search was performed in Medline, PubMed, BioMed Central and Embase up to February 2003, supplemented by a manual search of major relevant journals. Assessment was according to modified criteria for literature searching, eligibility criteria, validity assessment, data extraction and presentation. Five parameters were used to assess the quality of the meta-analyses in handling between-study heterogeneity. RESULTS: Of 84 potentially relevant citations, 47 were systematic reviews and of them 38 were meta-analyses. Of these 38 studies, 15 (39.5%) had conducted a literature search of multiple databases and 34 (89.5%) had conducted a supplementary manual search. The eligibility criteria were clearly presented in 81.6% of studies, but the quality of the primary studies was assessed in only 26.3%. The process and strategy for data extraction was reported in 57.9% of all studies; 19 (50%) studies planned statistical tests of between-study homogeneity and the results were reported in 18, but the level of statistical significance was reported in only 11 (57.9%). The selection of and justification for a statistical model was presented in 39.5% and 26.3% of studies, respectively. Among the 11 meta-analyses in which statistical between-study heterogeneity was reported, 54.5% ignored the statistical findings and proceeded to pool the study results. The implications of between-study heterogeneity were discussed in only 8 studies. CONCLUSIONS: Many methodological flaws were identified in the meta-analyses of H. pylori-related clinical studies, particularly for assessing, reporting and interpreting between-study heterogeneity. This warrants consistent and urgent adherence by reviewers and journal editors to the methodological guidelines for meta-analyses.
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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 | 0.345 | 0.639 |
| Meta-epidemiology (narrow) | 0.005 | 0.004 |
| Meta-epidemiology (broad) | 0.020 | 0.035 |
| Bibliometrics | 0.029 | 0.012 |
| Science and technology studies | 0.002 | 0.004 |
| Scholarly communication | 0.008 | 0.006 |
| Open science | 0.008 | 0.003 |
| Research integrity | 0.006 | 0.004 |
| 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; the direct Gemma label and the distilled Codex classifier agree on what is shown here.
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".