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.