title: Prevalence of diabetic retinopathy within a national diabetic retinopathy screening service.
abstract: OBJECTIVE
  Determine the prevalence and severity of diabetic retinopathy (DR) and risk factors in a large community based screening programme, in order to accurately estimate the future burden of this specific and debilitating complication of diabetes.
  
  
  METHODS
  A cross-sectional analysis of 91,393 persons with diabetes, 5003 type 1 diabetes and 86,390 type 2 diabetes, at their first screening by the community based National Diabetic Retinopathy Screening Service for Wales from 2005 to 2009. Image capture used 2×45° digital images per eye following mydriasis, classified by qualified retinal graders with final grading based on the worst eye.
  
  
  RESULTS
  The prevalence of any DR and sight-threatening DR in those with type 1 diabetes was 56.0% and 11.2%, respectively, and in type 2 diabetes was 30.3% and 2.9%, respectively. The presence of DR, non-sight-threatening and sight-threatening, was strongly associated with increasing duration of diabetes for either type 1 or type 2 diabetes and also associated with insulin therapy in those with type 2 diabetes.
  
  
  CONCLUSIONS
  Prevalence of DR within the largest reported community-based, quality assured, DR screening programme, was higher in persons with type 1 diabetes; however, the major burden is represented by type 2 diabetes which is 94% of the screened population.
authors.affiliation: Diabetes Research Group, Swansea University, Swansea, Wales, UK.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Thomas
authors.affiliation: Institute of Primary Care and Public Health, Cardiff University, Cardiff, Wales, UK.
authors.forename: Frank D
authors.initials: FD
authors.lastname: Dunstan
authors.affiliation: Diabetes Research Group, Swansea University, Swansea, Wales, UK.
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Luzio
authors.affiliation: Institute of Molecular and Experimental Medicine, Cardiff University, Cardiff, Wales, UK.
authors.forename: Sharmistha Roy
authors.initials: SR
authors.lastname: Chowdhury
authors.affiliation: School of Optometry & Vision Sciences, Cardiff University, Cardiff, Wales, UK.
authors.forename: Rachel V
authors.initials: RV
authors.lastname: North
authors.affiliation: Department of Ophthalmology, Cardiff and Vale University Health Board, Cardiff, Wales, UK.
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Hale
authors.affiliation: Retired GP, Powys, Wales, UK.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Gibbins
authors.affiliation: Diabetes Research Group, Swansea University, Swansea, Wales, UK.
authors.forename: David R
authors.initials: DR
authors.lastname: Owens
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D003430:Cross-Sectional Studies; D003922:Diabetes Mellitus, Type 1 / Q000150:complications; D003924:Diabetes Mellitus, Type 2 / Q000150:complications; D003930:Diabetic Retinopathy / Q000145:classification / Q000175:diagnosis / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D009313:National Health Programs / Q000706:statistics & numerical data; D016017:Odds Ratio; D010781:Photography; D015995:Prevalence; D012307:Risk Factors; D012720:Severity of Illness Index; D014852:Wales / Q000453:epidemiology; D055815:Young Adult
keywords: Epidemiology; Public health; Retina