To evaluate the efficacy and safety of high-dose α-lipoic acid in the treatment of diabetic polyneuropathy with regards to sensory symptoms and nerve conduction velocity.
A total of 236 diabetics with symptomatic polyneuropathy were enrolled into this 5-center, randomized, double-blind and placebo-controlled study of α-lipoic acid 1800 mg daily (n = 117) or matching placebo (n = 119) for 12 weeks. The primary outcome was total symptom score (TSS). Secondary end points included nerve conduction velocity, individual symptom score, HbA1c and safety parameters. The above parameters were reviewed and recorded at zero point and after treatment for 2, 4, 8, 12 weeks separately.
73.27% patients with symptomatic polyneuropathy improved after treatment with α-lipoic acid for 12 weeks versus 18.27% with placebo. TSS declined by 2.6 ± 2.3 with α-lipoic acid. And it was more than 0.7 ± 1.4 versus placebo (P < 0.05). TSS decreased quickly after treatment with α-lipoic acid for 2 weeks (P < 0.05). And it was better than placebo. Individual symptom scores of pain, extremity numbness, burning sensation or resting abnormal sensations were significantly diminished as compared to those before treatment and placebo group (all P < 0.05). Nerve conduction velocity had no change. HbA1c further decreased at the end of trial after α-lipoic acid treatment (P < 0.05). The incidence rates of adverse effects were 25.4% vs 11.8% in the treatment and control groups. The major manifestation was burning sensation from throat to stomach (12.7%).
Oral treatment with high-dose α-lipoic acid for 12 weeks may improve symptoms in patients with diabetic polyneuropathy. Dose of 600 mg thrice daily for 2 weeks has marked effects with a reasonable safety.