Shortening the Alzheimer's Disease Assessment Scale Cognitive Subscale

Stephen Z. Levine, Yair Goldberg, Anat Rotstein, Myrto Samara, Kazufumi Yoshida, Andrea Cipriani, Takeshi Iwatsubo, Stefan Leucht, Toshiaki A. Furawaka

Research output: Contribution to journalArticlepeer-review

Abstract

Background-A short yet reliable cognitive measure is needed that sepearates treatment and placebo for treatment trials for Alzheimer's Disease. Hence we aimed to shorten the Alzheimer's Disease Assessment Scale Cognitive Subscale (ADAS-Cog) and test its use as an efficacy measure. Methods-Secondary data analysis of participant-level data from five pivotal clinical trials of donepezil compared with placebo for Alzheimer's disease (N=2,198). Across all five trials, cognition was appraised using the original 11-item ADAS-Cog. Statistical analysis consisted of sample characterization, Item Response Theory (IRT) to identify an ADAS-Cog short version, and mixed-effects models for repeated-measures analysis (MMRM) to examine the effect sizes of ADAS-Cog change on the original and short versions in the placebo vs. donepezil groups. Results-Based on IRT, a short ADAS-Cog was developed with seven items and two response options. The original and short ADAS-Cog correlated at baseline, weeks 12 and 24 at 0.7. Effect sizes based on mixed modeling showed that the short and original ADAS-Cog separated placebo and donepezil comparably (ADAS-Cog original ES = 0.33, 95% CI = 0.29, 0.40, ADAS-Cog short ES = 0.25, 95% CI =0.23, 0.34). Conclusions-IRT identified a short ADAS-cog version that separated donepezil and placebo, suggesting its clinical potential for assessment and treatment monitoring.

Original languageEnglish
JournalEuropean Psychiatry
DOIs
StatePublished - 23 Feb 2024

Bibliographical note

Publisher Copyright:
© 2024 Cambridge University Press. All rights reserved.

Keywords

  • Alzheimer's disease
  • assessment
  • clinical trials
  • cognition
  • Item response theory
  • psychometric

ASJC Scopus subject areas

  • Psychiatry and Mental health

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