Autonomic neuropathy in type I diabetes: influence of duration and other diabetic complications.

To evaluate the influence of duration on the development of autonomic neuropathy (AN) a group of type I diabetic patients (n = 58) who had been diagnosed between the ages of 15 and 25 years was investigated. The duration of diabetes varied from 2 months to 30 years (mean 13 years). AN tests included a deep breathing test (E/I ratio) and an orthostatic test on tilt table (acceleration and brake indices) and the results were corrected for age. A clear correlation between AN test and duration of diabetes was shown only for the E/I ratio (r = -0.44, p less than 0.001). On the other hand, deteriorations in the brake index were unrelated to the duration of diabetes and occurred early; 35% of the patients with a duration of 10 years or less showed an abnormal brake index. Autonomic test deviations were related to other diabetic complications. The E/I ratio and the acceleration index were especially low in patients with retinopathy as well as in patients with symptoms of AN if combined with peripheral neuropathy (PN). The brake index was low in patients with symptoms of AN independent of PN.