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May 20, 1998

Concerns About Run-in Periods in Randomized Trials

Author Affiliations

Copyright 1998 American Medical Association. All Rights Reserved. Applicable FARS/DFARS Restrictions Apply to Government Use.1998

JAMA. 1998;279(19):1526-1527. doi:10-1001/pubs.JAMA-ISSN-0098-7484-279-19-jbk0520

To the Editor.—The article by Dr Pablos-Méndez and colleagues1 on the external validity of randomized controlled trials with placebo run-in periods does not mention a serious potential ethical dilemma. What happens to the subject who responds well during the run-in single-blind placebo phase of, for example, a randomized controlled trial for treatment of depression or hypertension? Are subjects just informed that they responded to the placebo and not enrolled? Were patients in such trials, especially studies in which subjects are dropped if they respond to placebo, given proper informed consent? What exactly is the participant told before the trial and after being dropped? Does the informed consent in such trials include all "procedures to be followed" including the fact that there is a "deceptive" elimination period? Does the consent form describe the exact circumstances by which patients can be terminated without their consent? It is possible (or perhaps even likely) that some trials have informed consents that may not quite adhere to the Federal Register,2 not to mention the Nuremberg Code and the Declaration of Helsinki.

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