title: Progression of diabetes retinal status within community screening programs and potential implications for screening intervals.
abstract: OBJECTIVE
  This study aimed to follow the natural progression of retinal changes in patients with diabetes. Such information should inform decisions with regard to the screening intervals for such patients.
  
  
  METHODS
  An observational study was undertaken linking the data from seven diabetes retinal screening programs across the U.K. for retinal grading results between 2005 and 2012. Patients with absent or background retinopathy were followed up for progression to the end points referable retinopathy and treatable retinopathy (proliferative retinopathy).
  
  
  RESULTS
  In total, 354,549 patients were observed for up to 4 years during which 16,196 patients progressed to referable retinopathy. Of patients with no retinopathy in either eye for two successive screening episodes at least 12 months apart, the conditions of between 0.3% (95% CI 0.3-0.8%) and 1.3% (1.0-1.6%) of patients progressed to referable retinopathy, and rates of treatable eye disease were <0.3% at 2 years. The corresponding progression rates for patients with bilateral background retinopathy in successive screening episodes were 13-29% and up to 4%, respectively, in the different programs.
  
  
  CONCLUSIONS
  It may be possible to stratify patients for risk, according to baseline retinal criteria, into groups with low and high risk of their conditions progressing to proliferative retinopathy. Screening intervals for such diverse groups of patients could safely be modified according to their risk.
authors.affiliation: Ninewells Hospital and Medical School, Dundee, U.K. grahamleese@nhs.net.
authors.forename: Graham P
authors.initials: GP
authors.lastname: Leese
authors.affiliation: Gloucestershire Eye Unit, Gloucester, U.K.
authors.forename: Irene M
authors.initials: IM
authors.lastname: Stratton
authors.affiliation: Landmark Health Consulting, York, U.K.
authors.forename: Martin
authors.initials: M
authors.lastname: Land
authors.affiliation: Norwich Medical School, Norwich, U.K.
authors.forename: Max O
authors.initials: MO
authors.lastname: Bachmann
authors.affiliation: Norwich and Norfolk University Hospital, Norwich, U.K.
authors.forename: Colin
authors.initials: C
authors.lastname: Jones
authors.affiliation: Gloucestershire Eye Unit, Gloucester, U.K.
authors.forename: Peter
authors.initials: P
authors.lastname: Scanlon
authors.affiliation: University of Dundee, Dundee, U.K.
authors.forename: Helen C
authors.initials: HC
authors.lastname: Looker
authors.affiliation: Public Health England, London, U.K.
authors.forename: Brian
authors.initials: B
authors.lastname: Ferguson
mesh_terms: D000328:Adult; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology; D003930:Diabetic Retinopathy / Q000175:diagnosis* / Q000453:epidemiology; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D012160:Retina / Q000473:pathology; D012164:Retinal Diseases / Q000175:diagnosis / Q000453:epidemiology / Q000473:pathology; D012189:Retrospective Studies; D013997:Time Factors