1.4 Quality Assessment
Two independent reviewers (Z.H. and YN.L.) assessed the risk of bias in
each study according to the risk of bias tool in the Cochrane Handbook
for Systematic Reviews of Interventions (version 5.1.0); discrepancies
were resolved by discussion with a third investigator (J.H.). Six
domains assessed for each included study were as follows: (1) random
sequence generation and allocation concealment; (2) blinding of
participants and personnel; (3) blinding of outcome assessors; (4)
incomplete outcome data; (5) selective reporting; (6) other bias.