title: Utility-based estimates of the relative morbidity of visual impairment and angina.
abstract: OBJECTIVE
  To quantify and compare the reduction in quality of life due to visual impairment and angina using patient preferences (utilities).
  
  
  METHODS
  Using a standard time tradeoff method, we obtained utilities for current vision, monocular and binocular blindness, current angina, and moderate angina in 60 patients with both vision problems and angina pectoris who sought care at the National Eye Institute (NEI), National Naval Medical Center, or Barnes-Jewish Hospital. Patients were characterized clinically based on visual acuity and the Duke Activity Status Index (DASI). Patients also completed a seven-item version of the NEI Visual Functioning Questionnaire and the SF-36 Health Survey Questionnaire.
  
  
  RESULTS
  Patients had a median visual acuity of 20/100 in the worst eye, 20/40 in the better eye, and a median DASI of 24.2 (0 = severe functional limitations due to anginal symptoms, 58.2 = no limitations). There was substantial variation in utilities among patients. The average utility for current vision (relative to ideal vision [= 1.0] and death [= 0.0]) was 0.82; the average utility for current angina (relative to no angina symptoms [= 1.0] and death [ = 0.0]) was 0.89. Among 26 patients with both visual impairment and recent anginal symptoms, the decrement in utility (on a scale ranging from ideal health [= 1.0] to death [= 0.0]) imposed by current visual impairment was greater than that imposed by current angina symptoms (0.146 versus 0.072, p=0.08, Wilcoxon signed rank test). The decrement in utility associated with binocular blindness was greater than the decrement associated with the symptoms of moderate angina (0.477 versus 0.039, p<0.0001).
  
  
  CONCLUSIONS
  Clinical status is not a surrogate for patient preferences regarding vision impairment or angina. There is substantial variation in utilities within the study population for both experienced and theoretical impairment states which is not explained by variations in clinical status. Some states of visual impairment may pose a greater quality of life burden than anginal symptoms. Because patient preferences for vision vary greatly, individual assessment is warranted for consideration in therapeutic decision making.
authors.affiliation: Division of General Medical Sciences, Department of Internal Medicine, Laboratory for Medical Decision Sciences, Washington University Medical School, St. Louis, Missouri, United States of America. nease@osler.wustl.edu
authors.forename: R F
authors.initials: RF
authors.lastname: Nease
authors.forename: S M
authors.initials: SM
authors.lastname: Whitcup
authors.forename: L B
authors.initials: LB
authors.lastname: Ellwein
authors.forename: G
authors.initials: G
authors.lastname: Fox
authors.forename: B
authors.initials: B
authors.lastname: Littenberg
mesh_terms: D000368:Aged; D000787:Angina Pectoris / Q000453:epidemiology*; D001766:Blindness / Q000453:epidemiology; D015991:Epidemiologic Measurements; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008396:Maryland / Q000453:epidemiology; D008875:Middle Aged; D008923:Missouri / Q000453:epidemiology; D009017:Morbidity; D017060:Patient Satisfaction; D011788:Quality of Life; D014786:Vision Disorders / Q000453:epidemiology*; D014792:Visual Acuity