Quality assessment and publication bias
We assessed the quality of the included trials based on the information
in the Methods section and supplementary materials about them. The
quality of the RCTs was assessed using the Cochrane Collaboration’s
risk-of-bias tool for randomized trials (RoB) (11), which consists of
six domains and allowance for any other bias, with risk-of-bias
judgements for RCTs ranging from ”high,” ”unclear” to ”low.” We assessed
observational studies using the Newcastle-Ottawa Scale (12) with scores
ranging from 0 to 9 points (a higher score indicated less bias). Two
authors independently assessed the studies’ quality and resolved
disagreements through consensus.
We used funnel plots to assess publication bias, which were calculated
using RevMan 5.3 software. The Egger regression test was used to measure
funnel plot asymmetry, and was calculated using Stata 12.0 (StataCorp
LP, College Station TX, USA).