title: Prevalence of diabetic retinopathy in mainland China: a meta-analysis.
abstract: BACKGROUND
  Although diabetic retinopathy (DR) is considered to be a major cause of blindness, this is the first meta-analysis to investigate the pooled prevalence of DR in mainland China.
  
  
  RESULTS
  We conducted a search of all English reports on population-based studies for the prevalence of DR using Medline, EMbase, Web of Science, Google (scholar), and all Chinese reports were identified manually and on-line using CBMDisc, Chongqing VIP database, and CNKI database. A meta-analysis was carried out. The fixed effects model or random effects model was used as a statistical test for homogeneity. Nineteen studies were included. The prevalence of DR, non-proliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR) in the pooled general population was 1.3% (95%CI: 0.5%-3.2%), 1.1% (95%CI: 0.6%-2.1%), and 0.1% (95%CI: 0.1%-0.3%), respectively, but was 23% (95%CI: 17.8%-29.2%), 19.1% (95%CI: 13.6%-26.3%), and 2.8% (95%CI: 1.9%-4.2%) in the diabetic group. The prevalence rate of DR in the pooled rural population was higher than that in the urban population, 1.6% (95%CI: 1.3%-2%), and the diabetic population, 29.1% (95%CI: 20.9%-38.9%). The prevalence of DR was higher in the Northern region compared with the Southern region.
  
  
  CONCLUSIONS
  The prevalence of DR in mainland China appeared a little high, and varied according to area. NPDR was more common. This study highlights the necessity for DR screening in the rural areas of China.
authors.affiliation: Department of Ophthalmology, The First Hospital of China Medical University, Shenyang, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Wu
authors.forename: Limin
authors.initials: L
authors.lastname: Liu
authors.forename: Jin
authors.initials: J
authors.lastname: Geng
authors.forename: Zhe
authors.initials: Z
authors.lastname: Yuan
authors.forename: Zhongyan
authors.initials: Z
authors.lastname: Shan
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002681:China / Q000453:epidemiology; D016206:Databases, Bibliographic; D048909:Diabetes Complications; D003920:Diabetes Mellitus / Q000453:epidemiology; D003930:Diabetic Retinopathy / Q000145:classification / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D005843:Geography; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D012424:Rural Population; D014505:Urban Population