2.3 Statistical analysis
Review Manager 5.3 (Cochrane,
London, UK) was used to perform data analysis using random effects
models. Statistical heterogeneity was assessed using the
I2 statistic. Sensitivity analyses were conducted to
identify potential heterogeneity by leaving out any study. Publication
bias was evaluated by generating a funnel plot of the logarithm of
effect size against the standard error for each trial.
P < 0.05 was considered statistically significant in all analyses.