This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Saved Citations Download to citation manager Request Permissions Request Reprints Add to My Marked Citations Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Citing Articles via Scopus Google Scholar Articles by Dinnett, E. M Search for Related Content PubMed PubMed Citation Articles by Dinnett, E. M Social Bookmarking                         What's this?

Unblinding of trial participants to their treatment allocation: lessons from the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER)

Moira MB Mungall

Jane A Kent

Elizabeth S Ronald

Karen E McIntyre

Clinical Trials Unit, Glasgow Royal Infirmary, Glasgow, UK

Elizabeth Anderson

Robertson Centre for Biostatistics, University of Glasgow, Glasgow, UK

Allan Gaw

Clinical Trials Unit, 4th Floor Walton Building, Glasgow Royal Infirmary, Glasgow G4 OSF, UK Allan.Gaw{at}ctunit.co.uk

PROSPER Study Group

Background The gold standard clinical trial design is the double-blind, randomized, controlled trial. No standard practice exists for the "unblinding" of trial participants and no legal obligation is placed on investigators to inform participants of their treatment allocation or study results at the end of a trial. Here we document our experiences of unblinding the 2520 Scottish participants in the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER).

Methods The objectives of the PROSPER unblinding process were to provide all study participants with their study medication status and on-trial cholesterol levels and to respect the rights of participants not to be unblinded. It was considered imperative by the study executive that the blind was maintained until the presentation and publication of the results. Staff therefore remained "blinded" throughout the unblinding process. Inappropriate contact with the PROSPER participants was avoided by confirming their current vital status and health status.

Results To coincide with the presentation of the PROSPER results, all participants, for whom it was deemed appropriate, were sent a summary of the results and were offered the opportunity to be advised of their treatment allocation and on-trial lipid profiles. The majority of participants opted for telephone unblinding. All primary care physicians who had patients randomised to the study were also sent a summary of the study results and sealed documents detailing the treatment allocation and lipid profiles for each patient. Relocated patients were traced and the information forwarded to their new primary care physicians.

Conclusion The dissemination of study results and treatment allocation to study participants is an integral part of the research process and should be included in the design of any clinical trial.

Clinical Trials, Vol. 2, No. 3, 254-259 (2005)
DOI: 10.1191/1740774505cn089oa


CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				E. M Dinnett, M. M B Mungall, C. Gordon, E. S Ronald, and A. Gaw Patients need not give consent in all clinical education. BMJ, March 4, 2006; 332(7540): 549 - 549. [Full Text]