Effect of intensive diabetes therapy on the progression of diabetic retinopathy in patients with type 1 diabetes: 18 years of follow-up in the DCCT/EDIC

Diabetes. 2015 Feb;64(2):631-42. doi: 10.2337/db14-0930. Epub 2014 Sep 9.


The Diabetes Control and Complications Trial (DCCT) demonstrated that a mean of 6.5 years of intensive therapy aimed at near-normal glucose levels reduced the risk of development and progression of retinopathy by as much as 76% compared with conventional therapy. The Epidemiology of Diabetes Interventions and Complications study (EDIC) observational follow-up showed that the risk of further progression of retinopathy 4 years after the DCCT ended was also greatly reduced in the former intensive group, despite nearly equivalent levels of HbA1c, a phenomenon termed metabolic memory. Metabolic memory was shown to persist through 10 years of follow-up. We now describe the risk of further progression of retinopathy, progression to proliferative diabetic retinopathy, clinically significant macular edema, and the need for intervention (photocoagulation or anti-VEGF) over 18 years of follow-up in EDIC. The cumulative incidence of each retinal outcome continues to be lower in the former intensive group. However, the year-to-year incidence of these outcomes is now similar, owing in large part to a reduction in risk in the former conventional treatment group.

Trial registration: ClinicalTrials.gov NCT00360815 NCT00360893.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adolescent
  • Adult
  • Aging
  • Diabetes Mellitus, Type 1 / drug therapy*
  • Diabetic Retinopathy / pathology*
  • Diabetic Retinopathy / prevention & control
  • Drug Administration Schedule
  • Female
  • Glycated Hemoglobin / genetics
  • Glycated Hemoglobin / metabolism
  • Humans
  • Insulin / administration & dosage
  • Insulin / therapeutic use*
  • Male
  • Middle Aged
  • Risk Factors
  • Young Adult


  • Glycated Hemoglobin A
  • Insulin
  • hemoglobin A1c protein, human

Associated data

  • ClinicalTrials.gov/NCT00360815
  • ClinicalTrials.gov/NCT00360893