The Impact of Diabetes and its Treatment on Cognitive Function among Adolescents Who Participated in the DCCT

Abstract

Objective: To evaluate whether severe hypoglycemia or intensive therapy affects cognitive performance over time in a subgroup of patients who were 13-19 years old at entry to the Diabetes Control and Complications Trial (DCCT).

Research Design and Methods: Longitudinal study involving 249 patients with type 1 diabetes who were between 13-19 years old when randomized into the DCCT. Scores on a comprehensive battery of cognitive tests obtained during the Epidemiology of Diabetes Interventions and Complications (EDIC) follow-up study, approximately 18 years later, were compared with baseline performance. We assessed the effects of the original DCCT treatment-group assignment, mean HbA1c values, and frequency of severe hypoglycemic events on eight domains of cognition.

Results: There were a total of 294 reported episodes of coma or seizure. Neither frequency of hypoglycemia nor previous treatment group was associated with decline on any cognitive domain. As in a previous analysis of the entire study cohort, higher HbA1c values were associated with declines in Psychomotor Efficiency (P<0.01); however, the previous finding of improved motor speed with lower HbA1c values was not replicated in this subgroup analysis.

Conclusions: Despite relatively high rates of severe hypoglycemia, cognitive function did not decline over an extended period of time in the youngest cohort of patients with type 1 diabetes.