2.5.2. Risk assessment of the included literature

The authors use the Cochrane collaboration of bias risk assessment tools to evaluate each other law quality, and the bias risk assessment included in the study are available from the following aspects: the formation of sequence, allocation concealment, the result data is imperfect, the interpretation of the results, the wrong data coding, and other bias. The bias can be divided into 3 risks: high risk, low risk, and uncertain risk.