Alpha-lipoic acid in the treatment of autonomic diabetic neuropathy (controlled, randomized, open-label study).

OBJECTIVE

to evaluate the effect of alpha-lipoic acid in autonomic diabetic neuropathy in a controlled, randomized, open-label study.

METHODS

46 patients with type 1 diabetes and different forms of autonomic neuropathy, of mean age 38.1 +/- 12.5 years and mean duration of diabetes 16.8 +/- 8.9 years were treated with alpha-lipoic acid for 10 days 600mg daily iv, thereafter one film tablet of 600mg daily for 50 days. 29 type 1 diabetic patients with autonomic diabetic neuropathy, of mean age 40.2 +/- 9.3 years and mean duration of diabetes 15.4 +/- 7.9 years served as a control group. We have followed-up patients' complaints, Ewing's tests, laboratory parameters of oxidative stress.

RESULTS

There was a significant improvement after treatment in the score for severity of cardiovascular autonomic neuropathy--from 6.43 +/- 0.9 to 4.24 +/- 1.8 (p<0.001), while in the control group it worsened from 6.18 +/- 1.3 to 6.52 +/- 0.9 (p>0.1). We found improvement in the Valsalva manoeuvre after treatment - from 1.05 +/- 0.04 to 1.13 +/- 0.08 (p<0.001); in the deep-breathing test -from 3.4 +/- 2.8 to 10.4 +/- 5.7 (p<0.001); and in the lying-to-standing test--from 0.99 +/- 0.01 to 1.01 +/- 0.02 (p>0.1), while in the control group there was no improvement. There was a beneficial effect of treatment on the change of systolic blood pressure at the lying-to-standing test--from 22.7 +/- 11.5 to 9.8 +/- 7.9 (p<0.001), while in the control group the change was 20.5 +/- 11.1 mmHg and 19.7 +/- 12.9 mmHg (p>0.1), respectively. We found improvement in diabetic enteropathy in six patients; in the complaints of dizziness, instability upon standing in six patients; in neuropathic edema of the lower extremities in four patients and in erectile dysfunction in four patients after treatment, while in the control group no change was reported in the symptoms and signs of autonomic neuropathy by the end of the follow-up period. There were changes in the laboratory parameters of oxidative stress after therapy--total serum antioxidant capacity increased from 20.42 +/- 1.8 to 22.96 +/- 2.3 microgH2O2/ml/min (p<0.05), serum SOD activity - from 269.8 +/- 31.1 to 319.8 +/- 29.IU/l (p=0.02) and erythrocyte SOD--from 0.89 +/- 0.10 to 1.11 +/- 0.09 U/gHb (p=0.04).

CONCLUSIONS

Our results demonstrate that alpha-lipoic acid (Thiogamma) appears to be an effective drug in the treatment of the different forms of autonomic diabetic neuropathy.