ReviewBMJ (Clinical research ed.)2013
Non-publication of large randomized clinical trials: cross sectional analysis.
Review in BMJ (Clinical research ed.), 2013. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 144 papers, 13 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
144 citing papers in PubMed, 13 syntheses or guidelines pooled it.
- Nonregistration, Discontinuation, and Nonpublication of Randomized Trials: A Systematic Review.JAMA network open · 2025Pooled it
- Time to publication for results of clinical trials.The Cochrane database of systematic reviews · 2024Pooled it
- Extracorporeal membrane oxygenation technology for adults: an evidence mapping based on systematic reviews.European journal of medical research · 2024Pooled it
- Pooled it
- Therapeutic Equivalence of Biosimilar and Reference Biologic Drugs in Rheumatoid Arthritis: A Systematic Review and Meta-analysis.JAMA network open · 2023Pooled it
- Publication bias examined in meta-analyses from psychology and medicine: A meta-meta-analysis.PloS one · 2019Pooled it
- Causes of reporting bias: a theoretical framework.F1000Research · 2019Pooled it
- Outcome switching in randomized controlled oncology trials reporting on surrogate endpoints: a cross-sectional analysis.Scientific reports · 2017Pooled it
- A systematic review of the processes used to link clinical trial registrations to their published results.Systematic reviews · 2017Pooled it
- Industry sponsorship and research outcome.The Cochrane database of systematic reviews · 2017Pooled it
- Clinical trials registries are underused in the pregnancy and childbirth literature: a systematic review of the top 20 journals.BMC research notes · 2016Pooled it
- Pooled it
- Barriers to and facilitators of interventions to counter publication bias: thematic analysis of scholarly articles and stakeholder interviews.BMC health services research · 2014Pooled it
- The insufficient publication of early-phase clinical trials in oncology.The oncologist · 2026Article
- Research waste in total knee arthroplasty studies: an observational study on registered trials.BMJ open · 2026Observational
- Salvaging information from paused or stopped clinical studies.Clinical trials (London, England) · 2025Article
- Development of a protocol complexity tool: a framework designed to stimulate discussion and simplify study design.BMC medical research methodology · 2025Article
- Barriers and facilitators to disseminating quality improvement and patient safety research: a scoping review.International journal for quality in health care : journal of the International Society for Quality in Health Care · 2025Article
- The meta-analysis and systematic review mirage: when data synthesis becomes data distortion.Supportive care in cancer : official journal of the Multinational Association of Supportive Care in Cancer · 2025Article
- The influence of the American Association for Thoracic Surgery on clinical trial development by cardiothoracic surgeons.The Journal of thoracic and cardiovascular surgery · 2025Article
84 more citing papers are in PubMed but not listed here.
Corrections and comments
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Authors and funding
6 authors.
Funding
Abstract
objectiveTo estimate the frequency with which results of large randomized clinical trials registered with ClinicalTrials.gov are not available to the public.
designCross sectional analysis
settingTrials with at least 500 participants that were prospectively registered with ClinicalTrials.gov and completed prior to January 2009. DATA SOURCES: PubMed, Google Scholar, and Embase were searched to identify published manuscripts containing trial results. The final literature search occurred in November 2012. Registry entries for unpublished trials were reviewed to determine whether results for these studies were available in the ClinicalTrials.gov results database.
main outcome measuresThe frequency of non-publication of trial results and, among unpublished studies, the frequency with which results are unavailable in the ClinicalTrials.gov database.
resultsOf 585 registered trials, 171 (29%) remained unpublished. These 171 unpublished trials had an estimated total enrollment of 299,763 study participants. The median time between study completion and the final literature search was 60 months for unpublished trials. Non-publication was more common among trials that received industry funding (150/468, 32%) than those that did not (21/117, 18%), P=0.003. Of the 171 unpublished trials, 133 (78%) had no results available in ClinicalTrials.gov.
conclusionsAmong this group of large clinical trials, non-publication of results was common and the availability of results in the ClinicalTrials.gov database was limited. A substantial number of study participants were exposed to the risks of trial participation without the societal benefits that accompany the dissemination of trial results.
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.