title: Diabetic retinopathy: contemporary prevalence in a well-controlled population.
abstract: OBJECTIVE
  To measure the extent to which modern intensified risk factor control has lessened the duration-specific prevalence of diabetic retinopathy and, therefore, has decreased the risk of blindness in Americans with type 2 diabetes.
  
  
  METHODS
  Intensified control of blood glucose and blood pressure has prevented diabetic retinopathy in randomized controlled trials. There is as yet no confirmation that subsequent treatment intensification in the community has had the same result. We identified all 6993 members of a health maintenance organization, Kaiser Permanente Northwest (KPNW), who, in 1997-1998, had dilated retinal examinations and verifiable data of diagnosis of type 2 diabetes. We plotted prevalence by time since diagnosis for background diabetic retinopathy (BDR) and proliferative diabetic retinopathy (PDR) and compared these results to identically derived 1980-1982 results from the Wisconsin Epidemiologic Study of Diabetic Retinopathy (WESDR). We estimated multivariate predictive models.
  
  
  RESULTS
  Mean (+/- SD) HbA(1c) in KPNW was 7.84 +/- 1.26% versus 10.37% (standardized) in the WESDR. KPNW blood pressure averaged 138.6 +/- 13.8/79.5 +/- 7.4 mmHg compared with 147.0/79.0 in the WESDR. BDR was much less prevalent in KPNW, but PDR prevalence appeared unchanged. BDR preceded diagnosis in 20.8% of the WESDR subjects but only 2.0% of KPNW subjects. However, in both populations, the first cases of PDR appeared similarly, soon after diagnosis.
  
  
  CONCLUSIONS
  Earlier diagnosis and more aggressive control of blood glucose and blood pressure decreased the duration-adjusted prevalence of background, but not of sight-threatening proliferative retinopathy. More population-based research is needed to replicate and explain this unexpected finding. Detecting and treating PDR should not be neglected on the assumption that risk-factor control has minimized its prevalence.
authors.affiliation: Center for Health Research, Kaiser Permanente Northwest Region, Portland, Oregon 97227-1110, USA. jonathan.brown@kpchr.org
authors.forename: Jonathan Betz
authors.initials: JB
authors.lastname: Brown
authors.forename: Kathryn L
authors.initials: KL
authors.lastname: Pedula
authors.forename: Kent H
authors.initials: KH
authors.lastname: Summers
mesh_terms: D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology*; D003930:Diabetic Retinopathy / Q000453:epidemiology* / Q000503:physiopathology; D006442:Glycated Hemoglobin / Q000032:analysis; D006279:Health Maintenance Organizations; D007196:Indiana / Q000453:epidemiology; D015995:Prevalence; D013997:Time Factors
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin