The following databases were searched for relevant randomised controlled trials (RCTs): China National Knowledge Infrastructure (CNKI), Web of Science, MEDLINE, PubMed, Embase, and Cochrane Central Register of Controlled Trials database (CENTRAL). 
CNKI
The following databases were searched for relevant randomised controlled trials (RCTs): China National Knowledge Infrastructure (CNKI), Web of Science, MEDLINE, PubMed, Embase, and Cochrane Central Register of Controlled Trials database (CENTRAL). 
Web of Science
The following databases were searched for relevant randomised controlled trials (RCTs): China National Knowledge Infrastructure (CNKI), Web of Science, MEDLINE, PubMed, Embase, and Cochrane Central Register of Controlled Trials database (CENTRAL). 
MEDLINE
The following databases were searched for relevant randomised controlled trials (RCTs): China National Knowledge Infrastructure (CNKI), Web of Science, MEDLINE, PubMed, Embase, and Cochrane Central Register of Controlled Trials database (CENTRAL). 
PubMed
The following databases were searched for relevant randomised controlled trials (RCTs): China National Knowledge Infrastructure (CNKI), Web of Science, MEDLINE, PubMed, Embase, and Cochrane Central Register of Controlled Trials database (CENTRAL). 
Embase
The following databases were searched for relevant randomised controlled trials (RCTs): China National Knowledge Infrastructure (CNKI), Web of Science, MEDLINE, PubMed, Embase, and Cochrane Central Register of Controlled Trials database (CENTRAL). 
Cochrane Central Register of Controlled Trials database