title: Sharing individual participant data from clinical trials: an opinion survey regarding the establishment of a central repository.
abstract: BACKGROUND
  Calls have been made for increased access to individual participant data (IPD) from clinical trials, to ensure that complete evidence is available. However, despite the obvious benefits, progress towards this is frustratingly slow. In the meantime, many systematic reviews have already collected IPD from clinical trials. We propose that a central repository for these IPD should be established to ensure that these datasets are safeguarded and made available for use by others, building on the strengths and advantages of the collaborative groups that have been brought together in developing the datasets.
  
  
  OBJECTIVE
  Evaluate the level of support, and identify major issues, for establishing a central repository of IPD.
  
  
  METHODS
  On-line survey with email reminders.
  
  
  METHODS
  71 reviewers affiliated with the Cochrane Collaboration's IPD Meta-analysis Methods Group were invited to participate.
  
  
  RESULTS
  30 (42%) invitees responded: 28 (93%) had been involved in an IPD review and 24 (80%) had been involved in a randomised trial. 25 (83%) agreed that a central repository was a good idea and 25 (83%) agreed that they would provide their IPD for central storage. Several benefits of a central repository were noted: safeguarding and standardisation of data, increased efficiency of IPD meta-analyses, knowledge advancement, and facilitating future clinical, and methodological research. The main concerns were gaining permission from trial data owners, uncertainty about the purpose of the repository, potential resource implications, and increased workload for IPD reviewers. Restricted access requiring approval, data security, anonymisation of data, and oversight committees were highlighted as issues under governance of the repository.
  
  
  CONCLUSIONS
  There is support in this community of IPD reviewers, many of whom are also involved in clinical trials, for storing IPD in a central repository. Results from this survey are informing further work on developing a repository of IPD which is currently underway by our group.
authors.affiliation: North West Hub for Trials Methodology Research, Department of Biostatistics, University of Liverpool, Liverpool, England.
authors.forename: Catrin
authors.initials: C
authors.lastname: Tudur Smith
authors.affiliation: North West Hub for Trials Methodology Research, Department of Biostatistics, University of Liverpool, Liverpool, England.
authors.forename: Kerry
authors.initials: K
authors.lastname: Dwan
authors.affiliation: Centre for Statistics in Medicine, University of Oxford, Oxford, England.
authors.forename: Douglas G
authors.initials: DG
authors.lastname: Altman
authors.affiliation: All-Ireland Hub for Trials Methodology Research, Queen's University, Belfast, Ireland.
authors.forename: Mike
authors.initials: M
authors.lastname: Clarke
authors.affiliation: School of Health and Population Sciences, University of Birmingham, Birmingham, England.
authors.forename: Richard
authors.initials: R
authors.lastname: Riley
authors.affiliation: North West Hub for Trials Methodology Research, Department of Biostatistics, University of Liverpool, Liverpool, England.
authors.forename: Paula R
authors.initials: PR
authors.lastname: Williamson
mesh_terms: D002986:Clinical Trials as Topic; D003625:Data Collection; D016208:Databases, Factual; D006801:Humans; D020407:Internet; D010358:Patient Participation; D011795:Surveys and Questionnaires