2.6 Data analysis
The Revman 5.3 software provided by Cochrane was used in this study. For
continuous variable data, the random effects model or fixed effects
model is used according to I2 of the combined total
results. I2was used to evaluate heterogeneity. We
considered that when I2 is
greater than 50%, there is a large inter-group heterogeneity, so the
random effect model was applied; when I2 is less than
or equal to 50%, the inter-group heterogeneity is small, so the fixed
effect model can be selected. For dichotomous results, a 95% confidence
interval combined RR was used as a measure of efficacy. If the units of
the variables were the same, WMD was used. Otherwise, we preferred to
choice SMD.