Statistical Analysis
This meta-analysis was performed using the Review Manager software
(RevMan V.5.3; Cochrane Collaboration, Oxford, UK). Cochrane Q
statistics and Chi-square test was used to determine whether
heterogeneity existed among studies. If the heterogeneity
(p<0.1, I² >50%), the random effects model was
used for meta-analysis. If there was no significant heterogeneity
between studies (P≥0.1, P≤50%), The fixed effects model is adopted. For
dichotomous variables, relative risk (RR) and 95% confidence interval
(CI) were used. For continuous variables, when the measuring tools and
units used in each document for an index are completely the same. The
weighted mean difference (WMD) and 95% CI were used to represent. When
they are not completely the same, standard mean difference (SMD) and
95% CI are used. A P<0.05
was considered to be statistically significant. For outcome where
quantitative data cannot be synthesized, narrative analysis is
performed. Since the number of studies that included the results of the
meta-analysis was not more than 10, we did not use funnel plot for
publication bias.