Botulinum Toxin-A for Painful Diabetic Neuropathy: A Meta-Analysis.

OBJECTIVES: Painful diabetic neuropathy (PDN) is a debilitating complication of diabetes that greatly affects the quality of life of those afflicted. There are many treatment options for neuropathic pain. Recent studies show a promising analgesic effect using botulinum toxin-A (BTX-A) for neuropathic pain.

METHODS: This article is a meta-analysis of two studies using BTX-A in the treatment of neuropathic pain. Electronic searches of MEDLINE/PubMed, EMBASE, and Cochrane Libraries using the terms "botulinum neurotoxin" and "neuropathic pain" were conducted. Only class I and class II therapeutic trials, as classified by the American Academy of Neurology were included. The primary outcome measured was the difference in visual analogue scale (VAS) from pre-intervention and post-intervention after 1 month. Data were analyzed for biases and heterogeneity following Cochrane and PRISMA guidelines.

RESULTS: Two studies on PDN were analyzed in the meta-analysis showing improvement of 1.96 VAS points (95% CI, -3.09 to -0.84; Z score = 3.43, P < 0.001) following treatment with BTX-A. This corresponds to clinically significant improvement of "minimum change in pain." The adverse effects of infection at injection site was not statistically significant (P = 0.49). BTX-A may be effective for PDN.

CONCLUSION: Tests for significance, low overall risk of bias, and almost no statistical heterogeneity suggests that there is a correlation between BTX-A and improvement of pain scores in PDN. Further large-scale controlled trials are needed.