Statistical Analysis
The Review Manager (RevMan) computer software [version 5.3];
Copenhagen: The Nordic Cochrane Centre, The Cochrane Collaboration,
2014; and R version 3.5.1 (R Development Core Team, 2010) was used to
perform the meta-analysis. Odds ratios were extracted and converted into
treatment effects and standard errors. The generic inverse variance
method and a random-effects model was utilized. Results are presented as
OR with 95% confidence intervals (CI). The consistency and
heterogeneity were assessed by calculating I2, and
publication bias was assessed by creating a funnel plot to evaluate for
the existence of small-study effects.