Herbal medicine (zhishi xiebai guizhi decoction) for unstable angina Protocol for a systematic review and meta-analysis

Background: Unstable angina (UA) is a clinically common coronary heart disease. Zhishi xiebai guizhi decoction (ZXGD) has been widely used in the management of UA, although its effective evidence is not clear and there is no systematic review regarding its efficacy and safety. Therefore, we conduct this systematic review protocol to evaluate the efficacy and safety of ZXGD in the treatment of UA. Methods: We will search the following electronic databases: Cochrane Library, Web of Science, PubMed, EBASE, Springer, WHO International Clinical Trial Registration Platform, China Biomedical Literature Database, China National Knowledge Infrastructure, Chinese Scientific Journal Database (VIP), and Wan-fang database from their inception to October 2018. Only randomized controlled trials (RCTs) published in English and Chinese will be included. Continuous data will be expressed as mean difference or standard mean difference, and dichotomous data relative as risk. Study selection, data extraction, and assessment with risk of bias and data analysis will be performed by two independent authors. RevMan software version 5.3 will be used for meta-analysis. Results: This study will provide high-quality evidence of ZXGD in the treatment of UA from the following aspects, including clinical efficacy, blood lipids, Seattle angina scale, electrocardiogram improvement, ST-segment depression, left ventricular ejection fraction, angina duration, and adverse events. Conclusion: This systematic review will provide a basis for judging whether ZXGD is an effective intervention for UA or not.