Evaluation of effectiveness of different modes of per os therapy of painful diabetic peripheral polyneuropathy with alpha-lipoic acid

Aim. To evaluate effectiveness of different modes of per os therapy of painful diabetic peripheral polyneuropathy with alpha-lipoic acid. Materials and methods. This work is a prospective open randomized comparative clinical study including 4 parallel groups of patients. Group 1 (n=31) comprised patients given 600 mg ALA daily (two 300 mg tablets at a time), group 2 (n=28) 600 mg ALA daily (two 300 mg tablets in succession), group 3 (n=35) 900 mg ALA daily (three 300 mg tablets at a time in the morning), group 4 (n=27) 900 mg ALA daily (three 300 mg tablets in succession 30-40 min before meals). Active treatment lasted 3 months. Results. Beneficial effect of 3 ALA tablets on neurologic symptoms estimated by NTSS-6 and 9 scales was significantly more pronounced than that of two 300 mg tablets taken either once or twice a day. The groups were analysed in terms of the number of patients who achieved or failed to achieve the end point of therapy ("responders", n=86 and "non-responders", n=29). The HbA1c level and the degree of sensory deficit were shown to be good predictors of therapeutic efficiency. There was moderate correlation between HbA1c level (>8%), NIS LL and NIS LL-sensory function points, and frequency of response to ALA therapy (r=0.251; p=0.007 //r=0.32; p=0.00077 //r=0.32; p=0.0015 respectively). Patients having HbA1c <7.0% showed maximum dynamics of NTSS-6 and 9 points. Conclusion. Intake of ALA tablets (300 mg thrice daily) causes marked reduction of neurologic symptoms estimated by NTSS-6 and 9 scales. The frequency of pain relapses depends on the initial HbA1c level rather than on the previous scheme of ALA therapy. High HbA1c (>8.0%) and severe disturbances of sensory function (e.g. monofilament resistance) may be used as predictors of therapeutic efficiency.