title: Can the general public use vignettes to discriminate between Alzheimer's disease health states?
abstract: BACKGROUND
  Valid estimates of health-related quality-of-life (HRQoL) are often difficult to obtain from persons with Alzheimer's disease (AD) and family caregiver proxies. To help assess whether the general public can serve as an alternate source of proxy HRQoL estimates in AD, we examined whether the general public can use vignettes to discriminate between AD health states.
  
  
  METHODS
  We administered a telephone survey to randomly recruited participants from the general public who were aged 18 years or older. Interviewers read vignettes describing the mild, moderate, and severe AD health states to the participants, who answered the EQ-5D-5L and Quality of Life-Alzheimer's Disease (QoL-AD) scales as if they had AD based on the vignette descriptions. Participants also answered the EQ-5D-5L for their current health states. We converted EQ-5D-5L responses into health utility scores using Canadian preference weights. We employed the Wilcoxon signed rank test to examine whether mean health utility scores and mean QoL-AD scores differed between health states. We used Pearson's r to assess correlations between health utility and QoL-AD scores.
  
  
  RESULTS
  Forty-eight participants (median age = 53 years; 25 female) completed the telephone interview; health utility and QoL-AD scores decreased as AD severity increased (p <0.0001). Mean health utility scores were 0.65 (mild), 0.51 (moderate), and 0.25 (severe). Mean QoL-AD scores were 26.7 (mild), 23.0 (moderate), and 17.4 (severe). The correlations between health utility and QoL-AD scores were moderate to strong (r ≥ 0.62).
  
  
  CONCLUSIONS
  Using the vignettes, the general public provided HRQoL estimates that discriminated between the three AD health states. This finding suggests the general public may be a promising source of proxy HRQoL estimates in place of persons with AD.
authors: School of Public Health and Health Systems, University of Waterloo, 200 University Avenue West, Waterloo, ON, Canada. moremus@uwaterloo.ca.
authors: Mark
authors: M
authors: Oremus
authors: Department of Clinical Epidemiology and Biostatistics, McMaster University, 1280 Main Street West, Hamilton, ON, Canada. fengxie@mcmaster.ca.|Program for Health Economics and Outcome Measures (PHENOM), 50 Charlton Avenue East, Hamilton, ON, Canada. fengxie@mcmaster.ca.|Centre for Evaluation of Medicines, St. Joseph's Healthcare Hamilton, 25 Main Street West, Hamilton, ON, Canada. fengxie@mcmaster.ca.
authors: Feng
authors: F
authors: Xie
authors: Child Health Evaluative Sciences, Hospital for Sick Children, 555 University Avenue, Toronto, ON, Canada. eleanor.pullenayegum@sickkids.ca.
authors: Eleanor
authors: E
authors: Pullenayegum
authors: Centre for Evaluation of Medicines, St. Joseph's Healthcare Hamilton, 25 Main Street West, Hamilton, ON, Canada. gaebk@mcmaster.ca.
authors: Kathryn
authors: K
authors: Gaebel
mesh_terms: D000328:Adult; D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000453:epidemiology* / Q000523:psychology; D002170:Canada / Q000453:epidemiology; D017028:Caregivers / Q000523:psychology; D005260:Female; D006304:Health Status; D006306:Health Surveys / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011788:Quality of Life / Q000523:psychology