During the subsequent observational follow-up of the DCCT cohort, in the Epidemiology of Diabetes Interventions and Complications (EDIC) study, the difference in the median A1C values between the original intensive and conventional therapy groups (7.2 and 9.1 percent, respectively) narrowed during follow-up (8.1 and 8.2 percent, respectively, by five years) 18 Thus, intensive insulin therapy for 6.5 years during the DCCT reduced the risk of retinopathy over at least the next 10 years compared with conventional therapy, despite an absence of a difference in A1C values during the post-DCCT trial period.