Efficacy of vitamin and antioxidant supplements for treatment of diabetic peripheral neuropathy: systematic review and meta-analysis of randomized controlled trials

ABSTRACT

The results of treatment effect of vitamin or antioxidant intake on diabetic peripheral neuropathy (DPN) was inconsistent. Therefore, we performed a meta-analysis of randomized controlled trials (RCTs) to examine whether these supplements are effective in DPN treatment. We searched seven databases from inception to October 2021. All RCTs of DPN treatments with vitamin and antioxidant supplements were included. We performed sensitivity and subgroup analysis, and also tested for publication bias by the funnel plot and Egger’s test. A total of 14 studies with 1384 patients were included in this systematic review. Three high-quality trials showed that vitamin and antioxidant supplements significantly increased sensory nerve conduction velocity (SNCV) of the sural nerve (MD = 2.66, 95%CI (0.60, 4.72), P < 0.05, I²= 0%). Seven studies (758 participants) suggested that these supplements might have improvement on motor nerve conduction velocity (MNCV) of the peroneal nerve in DPN patients with the random-effect model (MD = 0.60, 95%CI (0.28, 0.92), P < 0.05, I²= 65%). In four studies, these supplements could have improved on MNCV of the median nerve with the fixed-effect model (MD = 4.22, 95%CI (2.86, 5.57), P < 0.05, I²= 0%). However, ten studies (841 participants) have suggested that vitamin and antioxidant supplements have not decreased glycosylated haemoglobin (HbA1c). Vitamin and antioxidant supplements may improve the conduction velocity of nerves, including median, sural and peroneal nerves of patients with DPN. But these supplements have not decreased HbA1c in DPN patients. Several trials with a large sample size are needed to provide evidence support for clinical practice in the future.

KEYWORDS:

• Diabetic peripheral neuropathy
• vitamin
• antioxidant supplement
• randomized controlled trial
• meta-analysis
• sural nerve
• peroneal nerve
• median nerve

Acknowledgement

We deeply appreciate the Yanzhong Xue for putting forward extremely valuable comments for the whole paper in the revised draft.

Author contributions

Jinghong Huo and Xiaoying Dong: formal analysis and investigation; Jinming Lv: writing-original draft preparation; Lingyu Wu and Hua Gao: writing-review and editing, Xiuqin Yang and Huanhuan Liu: visualization and Supervision; Yanzhong Xue: check the sentence structure and grammar in the whole manuscript. Qinghan Gao: project administration. All authors have read and agreed to the published version of manuscript.

Data availability statement (DAS)

The data that support the findings of this study are available from the corresponding author, (Qinghan Gao), upon reasonable request.

Disclosure statement

No potential conflict of interest was reported by the author(s)

Additional information

Funding

This work was supported by Ningxia Natural Science Foundation, China, [grant number: 2021AAC03138]; The National Natural Science Foundation of China [grant number: 82060596].