Quantitative synthesis
The data of included literature was undertaken using Review Manager
V.5.4. Random effects models were used as a measure of the outcomes with
high heterogeneity, otherwise, use the fixed effects models. We
calculated the MD with a 95% CI and pooled the means and SD from
continuous results, OR with a 95% CI from dichotomous data. I2 value
and Q test was used to assessed the heterogeneity between all
statistical tests, which was showed with the forest plots. Heterogeneity
was regarded as to be low if I2<=30%, high
if I2>30%14. Galbraith’s diagram
performed the heterogeneity created by the circle beyond the lower and
upper lines. Subgroup sensitivity analysis was executed by excluding one
study for the purpose that evaluated the effect on the result. We
applied STATA V.12.1 to subsequent operations. The publication bias was
assessed with Egger’s test and funnel plot. All the reported p values
were two-side and it was considered statistically significant merely it
less than 0.05.