MRI substudy participation in alzheimer disease (AD) clinical trials: Baseline comparability of a substudy sample to entire study population

Rema Raman, Ronald G. Thomas, Michael W. Weiner, Clifford R. Jack, Karin Ernstrom, Paul S. Aisen, Pierre N. Tariot, Joseph F. Quinn

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

Objective: To determine if a self-selected group of participants who enroll in an imaging substudy of Alzheimer disease (AD) clinical trials is representative of the overall study sample. Methods: Baseline data from 2 ongoing AD clinical trials with 402 and 313 randomized participants were analyzed. Magnetic resonance imaging substudy enrollers (166 participants in trial 1 and 161 participants in trial 2) and nonenrollers were compared on baseline demographic, medical and clinical characteristics separately for the 2 trials. Results: In both trials, enrollers were statistically similar to nonenrollers on most demographic and clinical measures. One study sample showed that enrollers had lower cognitive scores at baseline when compared with nonenrollers: lower Mini Mental State Examination scores (20.15±3.6 vs. 21.04±3.6, P=0.02), and higher Alzheimer's Disease Assessment Scale-cognitive domain scores (24.99±8.5 vs. 23.03±9.3, P=0.03); however, the difference was not considered clinically important and was not observed in the second trial. Conclusions: The groups of individuals who agreed to participate in the imaging substudies of AD trials were remarkably comparable to the comparison groups at baseline on a wide range of demographic and clinical measures; there seems to be a minimal effect of self-selection bias. The Results indicate that it may be reasonable to generalize findings in an imaging substudy to the complete the study population.

Original languageEnglish (US)
Pages (from-to)333-336
Number of pages4
JournalAlzheimer disease and associated disorders
Volume23
Issue number4
DOIs
StatePublished - Oct 1 2009

Keywords

  • AD
  • MRI
  • Randomized clinical trials

ASJC Scopus subject areas

  • Clinical Psychology
  • Gerontology
  • Geriatrics and Gerontology
  • Psychiatry and Mental health

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