Data Extraction
Two investigators extracted the following information: basic information of included studies, baseline characteristics of study subjects, details of the intervention, length of follow-up, key elements of risk of bias assessment, and outcomes of interest. Disagreements were resolved through consensus and, if necessary, consultation with a third investigator (Y.Z.M.).
Quality Assessment
Two investigators independently assessed the risk of bias according to the Cochrane Collaboration risk of bias tool, including the following domains: sequence generation, allocation concealment, blinding of participants or personnel, blinding of outcome assessors, incomplete outcome data, selective outcome reporting, and other sources of bias. 14 We rated each criterion as ’low’ risk of bias, ’high’ risk of bias, or ’unclear’ risk of bias.