title: Development of a preference-based index from the National Eye Institute Visual Function Questionnaire-25.
abstract: OBJECTIVE
  Understanding how individuals value health states is central to patient-centered care and to health policy decision making. Generic preference-based measures of health may not effectively capture the impact of ocular diseases. Recently, 6 items from the National Eye Institute Visual Function Questionnaire-25 were used to develop the Visual Function Questionnaire-Utility Index health state classification, which defines visual function health states.
  
  
  OBJECTIVE
  To describe elicitation of preferences for health states generated from the Visual Function Questionnaire-Utility Index health state classification and development of an algorithm to estimate health preference scores for any health state.
  
  
  METHODS
  Nonintervention, cross-sectional study of the general community in 4 countries (Australia, Canada, United Kingdom, and United States). A total of 607 adult participants were recruited from local newspaper advertisements. In the United Kingdom, an existing database of participants from previous studies was used for recruitment.
  
  
  METHODS
  Eight of 15,625 possible health states from the Visual Function Questionnaire-Utility Index were valued using time trade-off technique.
  
  
  METHODS
  A θ severity score was calculated for Visual Function Questionnaire-Utility Index-defined health states using item response theory analysis. Regression models were then used to develop an algorithm to assign health state preference values for all potential health states defined by the Visual Function Questionnaire-Utility Index.
  
  
  RESULTS
  Health state preference values for the 8 states ranged from a mean (SD) of 0.343 (0.395) to 0.956 (0.124). As expected, preference values declined with worsening visual function. Results indicate that the Visual Function Questionnaire-Utility Index describes states that participants view as spanning most of the continuum from full health to dead.
  
  
  CONCLUSIONS
  Visual Function Questionnaire-Utility Index health state classification produces health preference scores that can be estimated in vision-related studies that include the National Eye Institute Visual Function Questionnaire-25. These preference scores may be of value for estimating utilities in economic and health policy analyses.
authors.affiliation: Evidera, Bethesda, Maryland.
authors.forename: Anne M
authors.initials: AM
authors.lastname: Rentz
authors.affiliation: Allergan Inc, Irvine, California.
authors.forename: Jonathan W
authors.initials: JW
authors.lastname: Kowalski
authors.affiliation: Allergan Inc, Irvine, California.
authors.forename: John G
authors.initials: JG
authors.lastname: Walt
authors.affiliation: Department of Medicine, University of California, Los Angeles.
authors.forename: Ron D
authors.initials: RD
authors.lastname: Hays
authors.affiliation: School of Health and Related Research, Sheffield University, Sheffield, England.
authors.forename: John E
authors.initials: JE
authors.lastname: Brazier
authors.affiliation: Evidera, Bethesda, Maryland.
authors.forename: Ren
authors.initials: R
authors.lastname: Yu
authors.affiliation: Duke University, Durham, North Carolina6now with Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor.
authors.forename: Paul
authors.initials: P
authors.lastname: Lee
authors.affiliation: Retina Division, Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Neil
authors.initials: N
authors.lastname: Bressler
authors.affiliation: Evidera, Bethesda, Maryland.
authors.forename: Dennis A
authors.initials: DA
authors.lastname: Revicki
mesh_terms: D000328:Adult; D000465:Algorithms; D003430:Cross-Sectional Studies; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D054554:National Eye Institute (U.S.); D011788:Quality of Life; D019057:Quality-Adjusted Life Years; D018434:Sickness Impact Profile; D011795:Surveys and Questionnaires; D014481:United States; D014792:Visual Acuity / Q000502:physiology