title: Utilities associated with diabetic retinopathy: results from a Canadian sample.
abstract: OBJECTIVE
  To report patient based utilities, using the time trade-off technique, associated with visual loss secondary to diabetic retinopathy in a sample of Canadian patients. In addition, to compare these utility values with a sample collected in a similar manner in a tertiary care practice in the United States.
  
  
  METHODS
  A cross sectional study of eligible patients with diabetic retinopathy presenting to a tertiary facility was performed. Demographic and clinical variables (including Snellen visual acuity), and utilities were collected both through chart review and standardised interviews with diabetic patients.
  
  
  RESULTS
  221 patients with diabetic retinopathy were eligible for this study and completed the interview. The mean age was 63.5 (SD 12.5) years, and 48.4% were female. Over 35% of the sample had visual acuity in the affected eye of 6/60 or worse. The mean utility for the sample was 0.79 (SD 0.23). The mean utility from this sample did not differ significantly from that obtained from a series of patients with diabetic retinopathy who were referred to a tertiary facility in the United States (mean 0.77, SD 0.21, p=0.313). Our cross border comparison had a power of 95% to detect a difference in utility of 0.1 between the two groups.
  
  
  CONCLUSIONS
  On average, Canadian patients with diabetic retinopathy were willing to trade off over 20% of their remaining lifespan in order to eliminate their ocular disease. The mean utility obtained from our sample of Canadian patients with diabetic retinopathy was not statistically different from that obtained from a similar sample of American patients.
authors.affiliation: The Cost-Effective Ocular Health Policy Unit, Queen's University, Hotel Dieu Hospital, Kingston, ON, Canada. sanjay_sharma60@hotmail.com
authors.forename: S
authors.initials: S
authors.lastname: Sharma
authors.forename: A
authors.initials: A
authors.lastname: Oliver-Fernandez
authors.forename: J
authors.initials: J
authors.lastname: Bakal
authors.forename: H
authors.initials: H
authors.lastname: Hollands
authors.forename: G C
authors.initials: GC
authors.lastname: Brown
authors.forename: M M
authors.initials: MM
authors.lastname: Brown
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002170:Canada; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D003930:Diabetic Retinopathy / Q000523:psychology*; D005260:Female; D006801:Humans; D007223:Infant; D008017:Life Expectancy; D008297:Male; D008875:Middle Aged; D017060:Patient Satisfaction; D011788:Quality of Life / Q000523:psychology*; D013997:Time Factors; D014481:United States; D014786:Vision Disorders / Q000523:psychology*; D014792:Visual Acuity