*2.5. Statistical Analysis*

The meta-analysis was conducted using the Review Manager, version 5.4EN (RevMan; The Cochrane Collaboration, Oxford, UK). The significance level was set at 0.05 for all analyses. When the continuous outcomes were reported in a study as median, range, and interquartile range, we estimated means and standard deviations using the formula described by Hozo et al. [15]. The mean difference (MD), odds ratio (OR) or relative risk (RR) and 95% confidence interval (CI) were used to estimate pooled results from studies. The Q and I2 statistic were used to investigate heterogeneity among the studies. A fixed model effect was used when I2 < 50%, and a random model effect was used in other cases.
