2.4. Risk of Bias and Validity Assessment

The study quality was evaluated using the Cochrane Collaboration risk of bias tool for RCTs. The tool included seven domains (such as random sequence generation, allocation concealment, blinding of participants and personnel, blinding of outcome assessment, incomplete data, selective reporting, and other bias) of assessment and are classified as low, unclear, or high risk. Due to the inclusion of limited studies, the publication bias was not assessed by funnel plot but done by Egger's test. The validity of the study was assessed by one of the authors (Weihong Wang) by using the GRADEpro GDT approach (https://gdt. http://gradepro.org/app) to summarize quality of the evidence.