This Article  • Full text  • PDF  • Send to a friend  • Save in My Folder  • Save to citation manager  • Permissions  Citing Articles  • Citation map  • Citing articles on HighWire  • Citing articles on Web of Science (5)  • Contact me when this article is cited  Related Content  • Related article  • Similar articles in JAMA  Social Bookmarking   What's this?

	Since this article does not have an abstract, we have provided the first 150 words of the full text and any section headings.

To the Editor.—Nobody would disagree with Dr Pablos-Méndez and colleagues¹ that nonadherence in a clinical trial adversely affects statistical efficiency.^2-3 We believe, however, that these authors do not adequately consider the impact of nonadherence on the validity of a randomized trial, and hence draw inappropriate inferences about generalizability. Since patients who do not comply obtain no benefit, nonadherence in a clinical trial will produce bias in the estimation of the true efficacy.^3-5 For this reason clinical trials use a variety of useful strategies, including a run-in period to identify and enroll subjects who will adhere. In the Physicians' Health Study,⁶ adherence during the run-in was the strongest predictor of adherence during the trial so prerandomization exclusion of nonadherers greatly enhanced validity. A successful run-in period in a trial enhances validity, which is a prerequisite for generalizability.

Pablos-Méndez and colleagues conclude that a run-in period to screen for adherence will . . . [Full Text of this Article]

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

RELATED ARTICLE

Run-in Periods in Randomized Trials: Implications for the Application of Results in Clinical Practice
Ariel Pablos-Méndez, R. Graham Barr, and Steven Shea
JAMA. 1998;279(3):222-225.
ABSTRACT | FULL TEXT  

THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES

Placebo response in clinical trials of depression and its implications for research on chronic neuropathic pain
Dworkin et al.
Neurology 2005;65:S7-S19.
ABSTRACT | FULL TEXT  

Ethical considerations concerning treatment allocation in drug development trials
Senn
Stat Methods Med Res 2002;11:403-411.
ABSTRACT  

Placebo-Associated Blood Pressure Response and Adverse Effects in the Treatment of Hypertension: Observations From a Department of Veterans Affairs Cooperative Study
Preston et al.
Arch Intern Med 2000;160:1449-1454.
ABSTRACT | FULL TEXT