Literature search

We will identify studies and trials from a highly sensitive literature search to identify all published and unpublished studies (Appendix in Table 1). The following databases will be searched from inception to present: MEDLINE; Embase; CENTRAL; Ichushi-Web; clinical trials registries (ClinicalTrials.gov, International Clinical Trials Registry Platform Search Portal (ICTRP), EU Clinical Trials Register, Japan Primary Registries Network (JPRN), China’s Clinical Trial Registry (ChiCTR)); China National Knowledge Infrastructure (www.cnki.net); Chongqing VIP Information Co., Ltd., formerly known as Database Research Center under Chongqing Branch of Institute of Scientific & Technical information of China (CB-ISTIC, www.wanfangdata.com.cn); HK government library (https://www.hkpl.gov.hk/en/e-resources/e-databases/keyword/e-database/all/1); Hyread full-text database of Taiwan (http://www.hyread.com.tw/hyreadnew/); Ericdata Higher Education Knowledge Base (http://www.ericdata.com/); Taiwan Journal Papers Index System (http://readopac.ncl.edu.tw/nclJournal/index.htm); TAO Taiwan Academic Online (http://tao.wordpedia.com/); and Ariti library (http://www.airitilibrary.com/).

We will search manually for additional studies by cross-checking the reference lists of all included primary studies and lists of relevant systematic reviews. In addition, study authors and experts will be contacted for additional studies. The search strategy will be developed by the research team in collaboration with an experienced librarian and checked by a referee according to the Peer Review of Electronic Search Strategies (PRESS) guidelines. The search strategy is shown in Appendix. Search results will be managed using Endnote (Clarivate Analytics, Philadelphia, PA).