Risk Factors for Retinopathy in Type 1 Diabetes: The DCCT/EDIC Study

Area of Science:

• Ophthalmology
• Endocrinology
• Diabetology

Background:

• The Diabetes Control and Complications Trial (DCCT) established intensive therapy's benefit for type 1 diabetes (T1D) in reducing retinopathy.
• Long-term follow-up in the Epidemiology of Diabetes Interventions and Complications (EDIC) study confirmed persistent advantages.

Purpose of the Study:

• To investigate modifiable and non-modifiable risk factors for diabetic retinopathy beyond glycemic control.
• To analyze retinopathy progression over 30 years of follow-up in the DCCT/EDIC cohort.

Main Methods:

• Kaplan-Meier survival analysis estimated event-free probabilities for proliferative diabetic retinopathy (PDR), clinically significant macular edema (CSME), and ocular surgery.
• Cox proportional hazards models identified risk factors, with multivariable models determined by forward- and backward-selection.

Main Results:

• Rates per 1,000 person-years were 12 for PDR, 14.5 for CSME, and 7.6 for ocular surgeries.
• Key risk factors for PDR included higher HbA1c, longer T1D duration, elevated albumin excretion rate (AER), and higher diastolic blood pressure (DBP).
• Higher HbA1c, longer T1D duration, and increased age and DBP were associated with CSME and ocular surgeries.

Conclusions:

• Mean HbA1c remains the most significant risk factor for retinopathy progression in T1D.
• Elevated AER and DBP are crucial modifiable risk factors, alongside glycemic control, for managing diabetic retinopathy.