Effects of intensive diabetes therapy on neuropsychological function in adults in the Diabetes Control and Complications Trial.

OBJECTIVE

To examine the effect of intensive therapy on neuropsychological performance in patients who participated in the Diabetes Control and Complications Trial (DCCT).

DESIGN

Multicenter, randomized, controlled clinical trial.

SETTING

29 DCCT clinical centers.

PATIENTS

1441 patients with insulin-dependent diabetes mellitus (IDDM) between 13 and 39 years of age who had had IDDM for 1 to 15 years and had no or minimal retinopathy or nephropathy at baseline. Volunteers were excluded if they had a history of substance abuse, psychological disturbance, or recurrent hypoglycemia with coma or seizure.

INTERVENTION

Intensive therapy with 3 or more daily insulin injections or continuous subcutaneous insulin infusion, guided by 4 or more glucose tests per day, compared with conventional therapy with 1 or 2 daily insulin injections.

OUTCOME MEASURES

Neuropsychological assessments were done at baseline; years 2, 5, and 7; and the end of the study. Eight cognitive domain scores were developed from the test results and were used to identify patients whose neuropsychological performance had clinically worsened.

RESULTS

Intensive therapy did not affect neuropsychological performance. In addition, patients who had repeated episodes of hypoglycemia did not perform differently than patients who did not have repeated episodes.

CONCLUSION

Intensive therapy and the attendant risk for hypoglycemia were not associated with neuropsychological impairment in the DCCT.