Comparison of intention-to-treat and per-protocol results in non-inferiority trials: a methodological review protocol
Bibliographic record
Abstract
INTRODUCTION: Non-inferiority (NI) trial designs, which assess whether an experimental intervention is no worse than the standard of care, have become increasingly prevalent in recent years. Current thinking suggests that the intention-to-treat (ITT) analysis is considered anti-conservative in the presence of protocol violations when compared with the per-protocol (PP) analysis. METHODS AND ANALYSIS: We aim to conduct a methodological review of NI trials to compare the results from ITT and PP analysis in NI trials. A comprehensive electronic search strategy will be used to identify studies indexed in MEDLINE, Embase and Cochrane Central Register of Controlled Trials databases. We will include 390 NI trials published prior to 31 December 2024. The primary outcomes are the treatment effect estimates from ITT and PP analyses. Secondary outcomes are the CI widths and the bounds of the CIs from the ITT and PP analyses. Analysis will calculate the relative difference in the point estimates, CI widths and CI bounds between the two approaches. Linear models will be used to investigate the relationship between the outcomes and the proportion of patients excluded from the PP analysis. ETHICS AND DISSEMINATION: This is a methodological review that has been registered on the International Prospective Register for Systematic Reviews (PROSPERO, CRD420251125360). Research ethics is not required as the project is a methodological review of previously published trials. Study findings will be shared via peer-reviewed publications and presentations at academic conferences.
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How this classification was reachedexpand
Direct model labels (unvalidated)
Per-model category and study-design labels from the labeling rounds. They are machine output, unvalidated, and the disagreement between models ships as data. No study design here is MEDLINE-validated yet.
| Model arm | Categories | Study design | Confidence |
|---|---|---|---|
| gemma | Metaresearch Domain: Methods · Genre: Protocol About the Canadian research system: no · About a Canadian topic: no | Systematic review | low |
| gpt | Metaresearch Domain: Methods · Genre: Protocol About the Canadian research system: no · About a Canadian topic: no | Systematic review | high |
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 | 0.333 | 0.464 |
| Meta-epidemiology (narrow) | 0.006 | 0.006 |
| Meta-epidemiology (broad) | 0.016 | 0.014 |
| Bibliometrics | 0.014 | 0.016 |
| Science and technology studies | 0.004 | 0.009 |
| Scholarly communication | 0.010 | 0.011 |
| Open science | 0.006 | 0.005 |
| Research integrity | 0.015 | 0.014 |
| Insufficient payload (model declined to judge) | 0.056 | 0.018 |
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, unvalidatedLabeled directly by 2 models reading the full record.
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".