Methods and analysis We will search the following 13 electronic databases from their inception. MEDLINE (PubMed), the Cochrane Central Register of Controlled Trials (CENTRAL), EMBASE, Allied and Complementary Medicine Database (AMED), China National Knowledge Infrastructure (CNKI), Wanfang, Journal Integration Platform (VIP) and six Korean Medical Databases (KoreaMed, the Korean Traditional knowledge Portal, OASIS, DBPIA, the Research Information Service System and the Korean Studies Information Service System) without restrictions on time or language. The data will be extracted independently by two authors using predefined criteria. Disagreements will be resolved by discussion between the authors. The risk of bias will be assessed using the Cochrane risk of bias tool.

Further consideration is needed to identify the most suitable study design and endpoints, which can lead to the development of pharmacological and nonpharmacological interventions that improve patients’ prognosis and outcomes.