THE EFFECT OF INTENSIVE DIABETES THERAPY ON MEASURES OF AUTONOMIC NERVOUS-SYSTEM FUNCTION IN THE DIABETES CONTROL AND COMPLICATIONS TRIAL (DCCT)

In the Diabetes Control and Complications Trial (DCCT), 1441 insulin-d ependent diabetic patients in the primary prevention and secondary int ervention cohorts were randomly assigned to either conventional or int ensive therapy and followed for up to 9 years. Baseline and biennial m easurements of autonomic function (R-R variation, Valsalva ratio, and postural testing) as well as quarterly assessment of autonomic symptom s were performed throughout the trial. There were no differences at ba seline between patients randomized to intensive vs conventional therap y. In general, autonomic abnormalities increased during the trial; how ever, R-R variation was less abnormal in the intensively treated secon dary intervention (7% with abnormal results at 46 years) compared with the conventionally treated group (14 % with abnormal results, p = 0.0 04) and in the combined cohorts (5 % of intensive treatment subjects w ith abnormal results vs 9 % of conventional treatment subjects, p = 0. 0017). There were few abnormal Valsalva ratios or postural tests al ba seline or during the trial. No significant difference in Valsalva rati o or postural tests occurred between the intensive and conventional tr eatment groups. Both the R-R variation and the Valsalva ratio had sign ificantly greater slopes of decline over time in the patients randomiz ed to conventional therapy (1.48 points per year and 0.015 per year, r espectively) compared to those randomized to intensive therapy (0.912 points per year and 0.0025 per year). Of the symptoms related to auton omic function, only incomplete bladder emptying was significantly more common in the conventional group. In summary, the DCCT documented tha t intensive therapy can slow the progression and the development of ab normal autonomic tests. Sy