Data synthesis and analysis
In present article, analyses were conducted using STATA software version
12.0 (Stata Corp, College Station, TX). Weighted mean difference (WMD)
and confidence interval (CI) of 95% were calculated for continuous
outcomes, while pooled odds ratios (ORs) and confidence interval (CI) of
95% were estimated for dichotomous outcomes. We used
I2 statistics to examine the heterogeneity of the
studies. The value of I2 was reported as a percentage
of total variation across studies, where I2> 50% indicates considerable heterogeneity. If no
heterogeneity was found between studies, a fixed-effect model was used
for meta-analysis. If there was significant heterogeneity among studies,
a random-effects model was utilized for the analysis. Sensitivity
analysis was performed by deleting each study sequentially to assess the
robustness of the combined estimates. Funnel plots, Begg’s and Egger’s
test were used to evaluate and test publication bias, respectively.