The effect of traditional Chinese medicine on gut microbiota in adults with type 2 diabetes A protocol for systematic review and meta-analysis

Background: Type 2 diabetes (T2DM), which is the major type of diabetes, accounts for more than 90% of all case of diabetes, and its pathogenesis remains inconclusive. Recent studies have revealed a significant role of gut microbiota in the onset and development of T2DM. Traditional Chinese medicine (TCM) has accumulated rich clinical experience in the treatment of T2DM for thousands of years and a large amount of studies have shown that TCM has the capacity of lowering blood glucose and modulating gut microbiota. The aim of this systematic review is to evaluate all randomized controlled trials on TCM for gut microbiota to assess the effectiveness and safety of TCM in T2DM patients. Methods: Seven electronic databases (Web of Science, PubMed, EMBASE, Cochrane Library, China National Knowledge Infrastructure, Wanfang Database, and VIP Information-Chinese Scientific Journal Database) will be searched from inception to present in the English and Chinese languages. Eligible randomized controlled trials evaluating the effect of TCM in T2DM patients, compared with western medicine, placebo or no intervention will be included in the study. The primary outcomes are the glucose metabolism and gut microbiota as well as its metabolites. The second outcomes are changes in weight, and changes in inflammatory markers. Two authors will independently select studies, extract data, and assess the quality of the studies by scanning the titles, abstracts, and full texts. The meta-analysis will be conducted using Review Manager version 5.3. The results will be presented as risk ratios for dichotomous data and adverse events, and as mean differences for continuous data. Result: The study will provide a summary of current evidence for the treatment of T2DM from the perspective of gut microbiota by using TCM based on the outcome measures. Conclusion: The systematic review will evaluate the efficacy of TCM in treating T2DM from the perspective of gut microbiota, providing current evidence and laying a foundation for further work in the field. PROSPERO registration number: CRD42020188043.