title: Evaluating the clinical relevance of a cognitive composite outcome measure: An analysis of 1414 participants from the 5-year GuidAge Alzheimer's prevention trial.
abstract: 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.
  
  
  
  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.
  
  
  
  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.
  
  
  
  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.
authors.affiliation: INSERM-University of Toulouse, UMR1027, Toulouse, France; Department of Epidemiology and Public Health, CHU Toulouse, Toulouse, France. Electronic address: nicola.coley@inserm.fr.
authors.forename: Nicola
authors.initials: N
authors.lastname: Coley
authors.affiliation: INSERM-University of Toulouse, UMR1027, Toulouse, France; Department of Epidemiology and Public Health, CHU Toulouse, Toulouse, France.
authors.forename: Adeline
authors.initials: A
authors.lastname: Gallini
authors.affiliation: INSERM-University of Toulouse, UMR1027, Toulouse, France; Department of Geriatric Medicine, CHU Toulouse, Gerontopole, Toulouse, France.
authors.forename: Pierre-Jean
authors.initials: PJ
authors.lastname: Ousset
authors.affiliation: INSERM-University of Toulouse, UMR1027, Toulouse, France; Department of Geriatric Medicine, CHU Toulouse, Gerontopole, Toulouse, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Vellas
authors.affiliation: INSERM-University of Toulouse, UMR1027, Toulouse, France; Department of Epidemiology and Public Health, CHU Toulouse, Toulouse, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Andrieu
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis*; D003071:Cognition; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D017063:Outcome Assessment, Health Care; D016032:Randomized Controlled Trials as Topic; D012189:Retrospective Studies
keywords: Clinical relevance; Clinical trials; Cognition; Cognitive composite score; Dementia; Outcome measures; Power; Preclinical Alzheimer's disease; Prevention