Evaluating the clinical relevance of a cognitive composite outcome measure: An analysis of 1414 participants from the 5‐year GuidAge Alzheimer's prevention trial. Issue 12 (13th July 2016)

• Record Type: Journal Article
• Authors: Coley, Nicola; Gallini, Adeline; Ousset, Pierre‐Jean; Vellas, Bruno; Andrieu, Sandrine
• Is Part Of: Alzheimer's & dementia. Volume 12:Issue 12(2016)
• Page Start: 1216
• Page End: 1225
• Publication Date: 2016-07-13
• Subjects: Cognitive composite score -- Clinical relevance -- Prevention -- Preclinical Alzheimer's disease -- Cognition -- Dementia -- Clinical trials -- Outcome measures -- Power; Alzheimer's disease -- Periodicals; Alzheimer Disease -- Periodicals; Dementia -- Periodicals; Démence; Maladie d'Alzheimer; Périodique électronique (Descripteur de forme); Ressource Internet (Descripteur de forme); 616.83
• DOI: 10.1016/j.jalz.2016.06.002
• Languages: English
• ISSNs: 1552-5260

Abstract

Abstract: Introduction: Composite cognitive scores have been developed as primary outcome measures for preclinical/prevention trials for Alzheimer's disease (AD), mainly using observational data and with little consideration of clinical relevance. Methods: Secondary analysis of placebo group data from a 5‐year AD prevention trial. The composite score was the average of the following z scores: MMSE orientation items, Free and Cued Selective Reminding Test, Category Fluency, Trail Making Test—part B. Results: Composite score change from baseline differed significantly by age, APOE genotype, and CDR progression and AD dementia status. A 1 point decrease in baseline score was highly predictive of 5‐year AD dementia risk (HR = 3.51, 95% CI, 2.62–4.71, P < .001). The 1 year minimum clinically important difference was estimated at −0.3 points and predicted AD dementia. Discussion: We explored the clinical relevance of a composite score in a prevention trial setting. This type of analysis facilitates the interpretation of composite scores and informs power calculations. Highlights: Baseline composite score was highly predictive of 5‐year AD dementia risk. Change from baseline differed by age, APOE, CDR progression, and AD dementia status. Two‐year practice effects were observed in nearly all subgroups. The 1‐year minimum clinically important difference was −0.3 points. This difference predicted 4‐year AD dementia risk.