Long-term efficacy of α-lipoic acid on cardiovascular autonomic function in type 2 diabetes 
Rumyana Dimova, Tsvetalina Tankova, Nevena Chakarova, Greta Grozeva, Lilia Dakovska 
Department of Diabetology, Clinical Centre of Endocrinology, Medical University, Sofia, Bulgaria
Abstract
Background: Although α-lipoic acid is the only pathophysiological agent for the treatment of diabetic neuropathy, the available randomized clinical studies provides no evidence for the long-term benefits from this therapy.
Aim: The present study aimed to evaluate the long-term efficacy of α-lipoic acid on cardio-vascular autonomic function in type 2 diabetes (T2D).
Method: A total of 94 subjects – 48 females and 46 males with T2D, of mean age 49.4±14.1 years, mean BMI 27.5±7.6 kg/m2, were included in a cross-sectional study. The participants were divided into two groups according to treatment – treated with α-lipoic acid for a period of five years and treatment-naïve. Anthropometric indices - height and weight were measured, and BMI was calculated. HbA1c was assessed in all participants (Roche Diagnostics). Autonomic function was evaluated by АNS-3.0 method, applying standard tests – deep breathing, Valsalva maneuver and standing from a seated position. 
Results: Lower prevalence of cardio-vascular autonomic dysfunction was found in subjects treated with α-lipoic acid - 36% in comparison to 63% (p=0.039) in treatment-naïve patients. The same trend was observed for clinical and subclinical postural hypotension. The percentage of pathological clinical tests and the number of abnormal autonomic tests per person were lower in α-lipoic acid treated group. The frequency-domain parameters demonstrated decreased sympathetic and parasympathetic tone at rest and during clinical tests in subjects not treated with α-lipoic acid.    
Discussion: The results of the present study have confirmed the long-term beneficial effect of α-lipoic acid on cardio-vascular autonomic function in subjects with T2D, independently of age, diabetes duration and obesity.