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.