title: Prevalence and determinants of undiagnosed diabetic retinopathy and vision-threatening retinopathy in a multiethnic Asian cohort: the Singapore Epidemiology of Eye Diseases (SEED) study.
abstract: OBJECTIVE
  To determine the prevalence and risk factors of undiagnosed diabetic retinopathy (DR), in particular vision-threatening DR (VTDR) in a multiethnic Asian cohort.
  
  
  METHODS
  A population-based survey of 3353 Chinese, 3280 Malays and 3400 Indians (73.6% response) aged 40-80 years residing in Singapore. Diabetes mellitus (DM) was defined as random glucose ≥11.1 mmol/L, use of diabetic medication or a previous physician diagnosis. DR severity was graded from retinal photographs following the modified Airlie House classification. VTDR was defined as the presence of severe non-proliferative DR (NPDR), proliferative DR (PDR) or clinically significant macular oedema (CSMO), using the Eye Diseases Prevalence Research Group definition. Participants were deemed 'undiagnosed' if they reported no prior physician diagnosis in structured interviews, in those with the condition.
  
  
  RESULTS
  Of 10 033 participants, 2376 had DM (23.7%), of which 805 (33.9%) had DR. Among 2376 with DM, 11.1% (n=263) were undiagnosed. Among 805 with DR, 671 (83.3%) were undiagnosed. Among 212 with VTDR, 59 (27.3%) were undiagnosed. In multivariate models, factors associated with undiagnosed VTDR were higher low-density lipoprotein (LDL) cholesterol (OR=1.53, 95% CI 0.99 to 2.35, p=0.05) and absence of visual impairment or blindness in any eye in terms of best-corrected vision OR=3.00, 95% CI 1.47 to 6.11, p=0.003).
  
  
  CONCLUSIONS
  In this community, a quarter with VTDR is undiagnosed, and 8 in 10 with any DR are undiagnosed, compared with only 1 in 10 with DM undiagnosed. These findings suggest that screening for diabetes is successful, while screening for DR is currently inadequate in our population. Public health strategies to aid early diagnosis of DR in Singapore are urgently warranted to reduce blindness due to diabetes.
authors.affiliation: Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.
authors.forename: Olivia S
authors.initials: OS
authors.lastname: Huang
authors.affiliation: Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.
authors.forename: Wan Ting
authors.initials: WT
authors.lastname: Tay
authors.affiliation: Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.
authors.forename: Peng Guan
authors.initials: PG
authors.lastname: Ong
authors.affiliation: Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.
authors.forename: Charumathi
authors.identifier: http://orcid.org/0000-0002-4042-4719
authors.initials: C
authors.lastname: Sabanayagam
authors.affiliation: Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.
authors.forename: Ching-Yu
authors.initials: CY
authors.lastname: Cheng
authors.affiliation: Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.
authors.forename: Gavin S
authors.initials: GS
authors.lastname: Tan
authors.affiliation: Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.
authors.forename: Gemmy C M
authors.initials: GC
authors.lastname: Cheung
authors.affiliation: Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore Center for Eye Research Australia, University of Melbourne, Melbourne, Royal Victorian Eye and Ear Hospital, Victoria, Australia.
authors.forename: Ecosse L
authors.initials: EL
authors.lastname: Lamoureux
authors.affiliation: Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore Center for Eye Research Australia, University of Melbourne, Melbourne, Royal Victorian Eye and Ear Hospital, Victoria, Australia Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
authors.forename: Tien Y
authors.initials: TY
authors.lastname: Wong
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People / Q000208:ethnology*; D001786:Blood Glucose / Q000378:metabolism; D003430:Cross-Sectional Studies; D003920:Diabetes Mellitus / Q000208:ethnology; D003930:Diabetic Retinopathy / Q000175:diagnosis* / Q000208:ethnology*; D005006:Ethnicity / Q000208:ethnology*; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D010781:Photography; D015995:Prevalence; D012307:Risk Factors; D012846:Singapore / Q000453:epidemiology; D011795:Surveys and Questionnaires; D014786:Vision Disorders / Q000175:diagnosis* / Q000208:ethnology*
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human
keywords: Epidemiology; Public health; Retina