title: Cost-Effectiveness of Screening for Intermediate Age-Related Macular Degeneration during Diabetic Retinopathy Screening.
abstract: OBJECTIVE
  To determine whether screening for age-related macular degeneration (AMD) during a diabetic retinopathy (DR) screening program would be cost effective in Hong Kong.
  
  
  METHODS
  We compared and evaluated the impacts of screening, grading, and vitamin treatment for intermediate AMD compared with no screening using a Markov model. It was based on the natural history of AMD in a cohort with a mean age of 62 years, followed up until 100 years of age or death.
  
  
  METHODS
  Subjects attending a DR screening program were recruited.
  
  
  METHODS
  A cost-effectiveness analysis was undertaken from a public provider perspective. It included grading for AMD using the photographs obtained for DR screening and treatment with vitamin therapy for those with intermediate AMD. The measures of effectiveness were obtained largely from a local study, but the transition probabilities and utility values were from overseas data. Costs were all from local sources. The main assumptions and estimates were tested in sensitivity analyses.
  
  
  METHODS
  The outcome was cost per quality-adjusted life year (QALY) gained. Both costs and benefits were discounted at 3%. All costs are reported in United States dollars ($).
  
  
  RESULTS
  The cost per QALY gained through screening for AMD and vitamin treatment for appropriate cases was $12,712 after discounting. This would be considered highly cost effective based on the World Health Organization's threshold of willingness to pay (WTP) for a QALY, that is, less than the annual per capita gross domestic product of $29,889. Because of uncertainty regarding the utility value for those with advanced AMD, we also tested an extreme, conservative value for utility under which screening remained cost effective. One-way sensitivity analyses revealed that, besides utility values, the cost per QALY was most sensitive to the progression rate from intermediate to advanced AMD. The cost-effectiveness acceptability curve showed a WTP for a QALY of $29,000 or more has a more than 86% probability of being cost effective compared with no screening.
  
  
  CONCLUSIONS
  Our analysis demonstrated that AMD screening carried out simultaneously with DR screening for patients with diabetes would be cost effective in a Hong Kong public healthcare setting.
authors: School of Public Health, The University of Hong Kong, Hong Kong, China.
authors: Christina K W
authors: CK
authors: Chan
authors: Department of Ophthalmology, The University of Hong Kong, Hong Kong, China. Electronic address: gangwani@hku.hk.
authors: Rita A
authors: RA
authors: Gangwani
authors: School of Public Health, The University of Hong Kong, Hong Kong, China.
authors: Sarah M
authors: SM
authors: McGhee
authors: School of Public Health, The University of Hong Kong, Hong Kong, China.
authors: JinXiao
authors: J
authors: Lian
authors: Department of Ophthalmology, The University of Hong Kong, Hong Kong, China.
authors: David S H
authors: DS
authors: Wong
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000975:Antioxidants / Q000008:administration & dosage; D003362:Cost-Benefit Analysis; D003930:Diabetic Retinopathy / Q000175:diagnosis* / Q000191:economics; D003941:Diagnostic Techniques, Ophthalmological / Q000191:economics*; D005260:Female; D017048:Health Care Costs; D006723:Hong Kong; D006801:Humans; D008268:Macular Degeneration / Q000175:diagnosis* / Q000188:drug therapy / Q000191:economics; D008297:Male; D008390:Markov Chains; D008403:Mass Screening / Q000191:economics*; D008875:Middle Aged; D010781:Photography; D019057:Quality-Adjusted Life Years; D012680:Sensitivity and Specificity; D014792:Visual Acuity; D017967:Zinc Compounds / Q000008:administration & dosage; D019207:beta Carotene / Q000008:administration & dosage
chemical_list: D000975:Antioxidants; D017967:Zinc Compounds; D019207:beta Carotene