Huangqi Guizhi Wuwu Decoction for treating diabetic peripheral neuropathy: a meta-analysis of 16 randomized controlled trials

Objective: This meta-analysis was performed to systematically assess the efficacy and safety of the Chinese herbal medicine Huangqi Guizhi Wuwu Decoction (HGWWD) for treating diabetic peripheral neuropathy. Data sources: Six electronic databases, including the Cochrane Library, MEDLINE database, Chinese Biomedical Database, Chinese National Knowledge Infrastructure Database, Chinese Science and Technique Journals Database, and the Wanfang Database, were searched on the internet for randomized controlled trials published up until 1 December 2015. The search terms included “Chinese herbal medicine”, “diabetic peripheral neuropathy” and “randomized controlled trials” in Chinese and in English. Data selection: We included randomized controlled trials using HGWWD/modified HGWWD for the treatment group, without restriction for the control group. We assessed literature quality in accordance with the Cochrane Review Handbook. A random or a fixed effects model was used to analyze outcomes using RevMan 5.2 software. Outcome measures: The primary outcomes were changes in symptoms and nerve conduction velocities. The secondary outcomes were fasting blood glucose and hemorheological indexes. Results: Sixteen randomized controlled trials, with a total of 1,173 patients, were included. Meta-analysis revealed that the efficacy of HGWWD for diabetic peripheral neuropathy was significantly superior compared with the control treatment (i.e., control group) (risk ratio = 0.36, 95% confidence interval (CI): 0.29–0.46, Z =8.33, P < 0.00001) Compared with the control group, there was an increase in median motor nerve conduction velocity (mean difference (MD) = 3.46, 95%CI: 1.88–5.04, Z = 4.30, P < 0.01) and median sensory nerve conduction velocity (MD = 3.30, 95%CI: 2.04–4.56, Z = 5.14, P < 0.01). There was also an increase in peroneal motor nerve conduction velocity (MD = 3.22, 95%CI: 2.45–3.98, Z = 8.21, P < 0.01) and peroneal sensory nerve conduction velocity (MD = 3.05, 95%CI: 2.01–4.09, Z = 5.75, P < 0.01) in the treatment groups. No significant difference in fasting blood glucose was found between the treatment groups and the control groups (MD = −0.12, 95%CI: −0.42–0.19, Z = 0.76, P = 0.45). Plasma viscosity was significantly decreased after treatment (MD = −0.11, 95%CI: −0.21 to −0.02, Z = 2.30, P = 0.02). No significant difference in fibrinogen was detectable (MD = −0.53, 95%CI: −1.28–0.22, Z = 1.38, P = 0.17). Four trials reported that treatment groups experienced no adverse reactions. Adverse events were not mentioned in the other 12 trials. No trial reported the incidence of complications, quality of life outcomes, or health economics. Conclusion: HGWWD treatment improves diabetic neurologic symptoms and ameliorates nerve conduction velocities. Our study suggests that HGWWD may have significant therapeutic efficacy for the treatment of diabetic peripheral neuropathy. However, the methodological quality of the randomized controlled trials was generally low. Larger and better-designed randomized controlled trials are required to more reliably assess the clinical effectiveness of HGWWD