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Compliance with requirement to report results on the EU Clinical Trials Register: cohort study and web resource

BMJ 2018; 362 doi: (Published 12 September 2018) Cite this as: BMJ 2018;362:k3218
  1. Ben Goldacre, senior clinical research fellow1,
  2. Nicholas J DeVito, researcher1,
  3. Carl Heneghan, professor2,
  4. Francis Irving, software engineer1,
  5. Seb Bacon, lead software engineer1,
  6. Jessica Fleminger, research student1,
  7. Helen Curtis, researcher1
  1. 1EBM DataLab, Nuffield Department of Primary Care Health Sciences, University of Oxford, Radcliffe Observatory Quarter, Oxford OX2 6GG, UK
  2. 2Centre for Evidence Based Medicine, Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK
  1. Correspondence to: B Goldacre ben.goldacre{at} (or @bengoldacre on Twitter)
  • Accepted 16 July 2018


Objectives To ascertain compliance rates with the European Commission’s requirement that all trials on the EU Clinical Trials Register (EUCTR) post results to the registry within 12 months of completion (final compliance date 21 December 2016); to identify features associated with non-compliance; to rank sponsors by compliance; and to build a tool for live ongoing audit of compliance.

Design Retrospective cohort study.

Setting EUCTR.

Participants 7274 of 11 531 trials listed as completed on EUCTR and where results could be established as due.

Main outcome measure Publication of results on EUCTR.

Results Of 7274 trials where results were due, 49.5% (95% confidence interval 48.4% to 50.7%) reported results. Trials with a commercial sponsor were substantially more likely to post results than those with a non-commercial sponsor (68.1% v 11.0%, adjusted odds ratio 23.2, 95% confidence interval 19.2 to 28.2); as were trials by a sponsor who conducted a large number of trials (77.9% v 18.4%, adjusted odds ratio 18.4, 15.3 to 22.1). More recent trials were more likely to report results (per year odds ratio 1.05, 95% confidence interval 1.03 to 1.07). Extensive evidence was found of errors, omissions, and contradictory entries in EUCTR data that prevented ascertainment of compliance for some trials.

Conclusions Compliance with the European Commission requirement for all trials to post results on to the EUCTR within 12 months of completion has been poor, with half of all trials non-compliant. EU registry data commonly contain inconsistencies that might prevent even regulators assessing compliance. Accessible and timely information on the compliance status of each individual trial and sponsor may help to improve reporting rates.


  • Contributors: BG conceived the project, designed the methods, conducted the analysis, wrote the paper, obtained funding, and supervised the project. FI built the website with input from SB, NJD, and BG. BG and NJD reviewed the legislation, with input from Darren Smyth. NJD extracted and processed the data in SQL, with input from BG, HC, SB, and JF. NJD normalised the sponsor names. BG, CH, NJD, and JF interpreted the findings. All authors contributed to and approved the final manuscript. BG is guarantor. This paper is compliant with the STROBE checklist. The corresponding author attests that all listed authors meet authorship criteria and that no others meeting the criteria have been omitted.

  • Funding: BG is funded by the Laura and John Arnold Foundation to conduct work on research integrity. No specific funding was sought for this project. The funder had no involvement in the study design or the decision to submit.

  • Competing interests: All authors have completed the ICMJE uniform competing interest form (available on request from the corresponding author) and declare: BG has received research funding from the Laura and John Arnold Foundation, the Wellcome Trust, the NHS National Institute for Health Research (NIHR) School of Primary Care, the Health Foundation, NHS England, the NIHR Oxford Biomedical Research Centre, and the World Health Organization; he also receives personal income from speaking and writing for lay audiences on the misuse of science. CH has received grant funding from WHO, the NIHR, and the NIHR School of Primary Care. BG and CH are cofounders of the AllTrials campaign. NJD, SB, and FI are employed on BG’s grant from the Laura and John Arnold Foundation.

  • Ethical approval: Not required.

  • Data sharing: All data can be viewed at The analytic code and software are shared freely for re-use under an open licence and can be viewed at

  • Transparency: The lead author (BG) affirms that the manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned have been explained.

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