StATS: Unblinding at the end of a study (created 2004-11-01).
When a study a placebo controlled study is completed, patients in both arms of the study are often offered the active drug at the end of the study at no cost as a way of thanking them for their participation. But some researchers want to continue to measure long term outcomes (outcomes that extend beyond the placebo phase of the study), so they will not reveal to the patients whether they received the active medication or placebo. This raises some difficult ethical issues. Here are a few references on this controversy that I saw on the IRBForum.
Fluoxetine, cognitive-behavioral therapy, and their combination for adolescents with depression: Treatment for Adolescents With Depression Study (TADS) randomized controlled trial. March J, Silva S, Petrycki S, Curry J, Wells K, Fairbank J, Burns B, Domino M, McNulty S, Vitiello B, Severe J. Jama 2004: 292(7); 807-20. [Medline]
The ethical problems of the open label extension study. Micetich KC. Camb Q Healthc Ethics 1996: 5(3); 410-4. [Medline]
Consent to open label extension studies: some ethical issues. Wainwright P. J Med Ethics 2002: 28(6); 373-6. [Medline] [Abstract] [Full text] [PDF]
This page was written by Steve Simon while working at Children's Mercy Hospital. Although I do not hold the copyright for this material, I am reproducing it here as a service, as it is no longer available on the Children's Mercy Hospital website. Need more information? I have a page with general help resources. You can also browse for pages similar to this one at Category: Blinding in research.