Prolonged effect of intensive therapy on the risk of retinopathy complications in patients with type 1 diabetes mellitus: 10 years after the Diabetes Control and Complications Trial.
OBJECTIVE
To examine the persistence of the original treatment effects 10 years after the Diabetes Control and Complications Trial (DCCT) in the follow-up Epidemiology of Diabetes Interventions and Complications (EDIC) study. In the DCCT, intensive therapy aimed at near-normal glycemia reduced the risk of microvascular complications of type 1 diabetes mellitus compared with conventional therapy.


METHODS
Retinopathy was evaluated by fundus photography in 1211 subjects at EDIC year 10. Further 3-step progression on the Early Treatment Diabetic Retinopathy Study scale from DCCT closeout was the primary outcome.


RESULTS
After 10 years of EDIC follow-up, there was no significant difference in mean glycated hemoglobin levels (8.07% vs 7.98%) between the original treatment groups. Nevertheless, compared with the former conventional treatment group, the former intensive group had significantly lower incidences from DCCT close of further retinopathy progression and proliferative retinopathy or worse (hazard reductions, 53%-56%; P < .001). The risk (hazard) reductions at 10 years of EDIC were attenuated compared with the 70% to 71% over the first 4 years of EDIC (P < .001). The persistent beneficial effects of former intensive therapy were largely explained by the difference in glycated hemoglobin levels during DCCT.


CONCLUSIONS
The persistent difference in diabetic retinopathy between former intensive and conventional therapy ("metabolic memory") continues for at least 10 years but may be waning.


BACKGROUND
(clinicaltrials.gov) Identifiers: NCT00360815 and NCT00360893.
White
Neil H
NH
Diabetes Unit, Massachusetts General Hospital, Boston, MA 02114, USA.
Sun
Wanjie
W
Cleary
Patricia A
PA
Danis
Ronald P
RP
Davis
Matthew D
MD
Hainsworth
Dean P
DP
Hubbard
Larry D
LD
Lachin
John M
JM
Nathan
David M
DM
D000293:Adolescent; D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000150:complications / Q000188:drug therapy*; D003930:Diabetic Retinopathy / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage*; D015994:Incidence; D007260:Infusion Pumps; D007328:Insulin / Q000008:administration & dosage*; D008297:Male; D015995:Prevalence; D012307:Risk Factors; D055815:Young Adult
D001786:Blood Glucose; D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents; D007328:Insulin; C517652:hemoglobin A1c protein, human