1.5 Synthesis of Evidence
We used the Reviewer Manager Software (version 5.3) for meta-analysis. We analyzed dichotomous variables with risk ratio (RR); for continuous variables, the mean difference (MD) was calculated with a 95% confidence interval (CI) and p value. We did χ2testing to assess the heterogeneities between studies (α=0.05), with ap value<0.05 orI 2>50% as being indicative of statistical heterogeneity. When a heterogeneity was detected, a random effect model was applied, and subgroup analysis was conducted to identify potential sources of heterogeneity. If a pvalue>0.05 or I 2<50%, a fixed effect model was conducted. Sensitivity analysis was conducted to test whether the results were was robust by excluding the study one by one and comparing the rest of the studies’ effects with all the studies’ total effects. Funnel plots were generated if there were sufficient studies included in the meta-analysis.