3.2 Risk of bias assessment
The quality of RCT was assessed according to the Cochrane Evaluation
Manual, including six aspects: randomization, allocation concealment,
blindness, incomplete data bias, selective reporting of results, and
other factors that may potentially affect authenticity. If the number of
people lost to follow-up exceeded 10% in the included study, the
possible causes of loss of follow-up were further analyzed and
intention-to-treat (ITT) analysis was performed. For each included
study, 3 evaluations were made for the above 6 items, namely, low bias
risk, high bias risk and unclear risk (Fig. 2).