ArticleBMC medicine2016
Association between trial registration and treatment effect estimates: a meta-epidemiological study.
Article in BMC medicine, 2016. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 30 papers, 7 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
30 citing papers in PubMed, 7 syntheses or guidelines pooled it.
- Registration and reporting characteristics of trials investigating exercise therapy following total knee arthroplasty: a systematic review.Acta orthopaedica · 2026Pooled it
- Perioperative dexmedetomidine for the prevention of postoperative delirium after cardiac surgery: a systematic review, Bayesian meta-analysis, and Bayesian re-analysis of the DECADE trial.British journal of anaesthesia · 2025Pooled it
- A systematic review and meta-analysis of strategies to promote vaccination uptake.Nature human behaviour · 2024Pooled it
- Assessing the magnitude of reporting bias in trials of homeopathy: a cross-sectional study and meta-analysis.BMJ evidence-based medicine · 2022Pooled it
- Does vaginal progesterone prevent recurrent preterm birth in women with a singleton gestation and a history of spontaneous preterm birth? Evidence from a systematic review and meta-analysis.American journal of obstetrics and gynecology · 2022Pooled it
- Trial-level characteristics associate with treatment effect estimates: a systematic review of meta-epidemiological studies.BMC medical research methodology · 2022Pooled it
- Registration of published randomized trials: a systematic review and meta-analysis.BMC medicine · 2018Pooled it
- Quality of evidence in a post-Soviet country: evaluation of methodological quality of controlled clinical trials published in national journals from Uzbekistan.BMC medical research methodology · 2020Trial
- Avoidable waste of research related to outcome planning and reporting in clinical trials.BMC medicine · 2018Trial
- A survey of researchers' attitudes to preregistration in animal research reveals multiple perceived barriers to adoption.PLoS biology · 2026Article
- Article
- The threat of serious outcome reporting bias in randomized controlled trials on acute ischemic stroke to evidence synthesis: a meta-epidemiological study.Cardiovascular diagnosis and therapy · 2025Review
- Harm effects in non-registered versus registered randomized controlled trials of medications: a retrospective cohort study of clinical trials.BMC medicine · 2024Article
- Supporting study registration to reduce research waste.Nature ecology & evolution · 2024Review
- Estimating the effect of COVID-19 on trial design characteristics: a registered report.Royal Society open science · 2023Article
- Declaration of common standards for the preregistration of animal research-speeding up the scientific progress.PNAS nexus · 2022Article
- Published trials of TACE for HCC are often not registered and subject to outcome reporting bias.JHEP reports : innovation in hepatology · 2021Article
- Trends in US pediatric mental health clinical trials: An analysis of ClinicalTrials.gov from 2007-2018.PloS one · 2021Article
- Fragility index of network meta-analysis with application to smoking cessation data.Journal of clinical epidemiology · 2020Article
- Prospective registration and reporting of trial number in randomised clinical trials: global cross sectional study of the adoption of ICMJE and Declaration of Helsinki recommendations.BMJ (Clinical research ed.) · 2020Article
Corrections and comments
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Authors and funding
5 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundTo increase transparency in research, the International Committee of Medical Journal Editors required, in 2005, prospective registration of clinical trials as a condition to publication. However, many trials remain unregistered or retrospectively registered. We aimed to assess the association between trial prospective registration and treatment effect estimates.
methodsThis is a meta-epidemiological study based on all Cochrane reviews published between March 2011 and September 2014 with meta-analyses of a binary outcome including three or more randomised controlled trials published after 2006. We extracted trial general characteristics and results from the Cochrane reviews. For each trial, we searched for registration in the report's full text, contacted the corresponding author if not reported and searched ClinicalTrials.gov and the International Clinical Trials Registry Platform in case of no response. We classified each trial as prospectively registered (i.e. registered before the start date); retrospectively registered, distinguishing trials registered before and after the primary completion date; and not registered. Treatment effect estimates of prospectively registered and other trials were compared by the ratio of odds ratio (ROR) (ROR <1 indicates larger effects in trials not prospectively registered).
resultsWe identified 67 meta-analyses (322 trials). Overall, 225/322 trials (70 %) were registered, 74 (33 %) prospectively and 142 (63 %) retrospectively; 88 were registered before the primary completion date and 54 after. Unregistered or retrospectively registered trials tended to show larger treatment effect estimates than prospectively registered trials (combined ROR = 0.81, 95 % CI 0.65-1.02, based on 32 contributing meta-analyses). Trials unregistered or registered after the primary completion date tended to show larger treatment effect estimates than those registered before this date (combined ROR = 0.84, 95 % CI 0.71-1.01, based on 43 contributing meta-analyses).
conclusionsLack of trial prospective registration may be associated with larger treatment effect estimates.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.