Non-pharmacologic treatments for symptoms of diabetic peripheral neuropathy: a systematic review – methodological issues are a matter for concern

Abstract

Dear Editor, We read with interest the study by Amato Nesbit et al.. Based on a systematic review, the authors assessed the efficacy and safety of non-pharmacologic treatments for symptoms of diabetic peripheral neuropathy (DPN). The study concluded that alpha-lipoic acid and spinal cord stimulation could improve pain; however, we would like to point out some issues in the study. The question involves the search strategy of acupuncture therapy studies. Acupuncture originated in China. After centuries of development, acupuncture gradually became one of the standard therapies used in Asia, Europe and the United States. Acupuncture, as a complementary and alternative therapy, has gained increased popularity for the treatment of DPN in China and other Eastern and Western countries. There are different types of acupuncture, including manual acupuncture, electroacupuncture (EA), laser acupuncture and so on. Clinical studies have shown that EA treatment has a significant effect on reducing pain, improving sleep disorders and quality of life in patients with PDN. Moreover, acupuncture treatment is well tolerated and safe. Animal experiments proved that protein kinase C (PKC)-mediated dorsal root ganglia (DRG) P2X3 receptor upregulation is a significant mechanism of PDN. EA plays an analgesic role by inhibiting the upregulation of PKC-dependent membrane P2X3 in DRG. To our knowledge, a systematic review about the effectiveness of manual acupuncture for treatment of DPN included 25 randomized control trials (RCTs) involving 1649 participants which were published in Chinese. However, this systematic review did not search the Chinese databases, such as Chinese Biomedical Literature Database (CBM), and only one acupuncture study which was published in an English language journal was included. The retrieval principle of systematic review is to find all relevant clinical studies in comprehensive way, and the original research database related to clinical research issues should be taken into account, and the language and time should not be limited. We suggest the searching strategy for MEDLINE as shown in Table 1. The Chinese translation of these search terms will be used to search the Chinese databases. DPN is a prevalent chronic complication of diabetes mellitus with significant clinical sequelae, which may cause serious harm to the health and reduce quality of life of the patients, and will gradually develop into a wide range of public health problems. In addition to the common approach of pharmacologic agents, identifying novel cost-effective options for management of DPN is an important priority for research in this area. Acupuncture may represent one component of a multimodal approach to effective management of DPN. However, the negative findings of a systematic review using inappropriate retrieval methods do not serve to elucidate the potential role of this otherwise safe and inexpensive treatment. In conclusion, we congratulate Amato Nesbit et al. on their contribution to provide evidence for non-drug treatments of DPN symptoms and encourage them to provide an updated systematic review and meta-analysis. Thus, researchers and health care policy experts can plan future research to better manage of type 2 diabetes.