2.9  |  Synthesis
The meta-analysis will be conducted using RevMan 5.4.Since the outcome indicators in this study are all continuous variables and the assessment tools for the outcome indicators are different, the standard mean difference (SMD) was chosen as the effect indicator and its 95% CI is provided.When SMD is used, if the direction of the unit of measure is opposite between the scales, the Measurement means of the corresponding scales were multiplied by -1 so that all scales had the same unit of measure orientation. The χ2 test andI2 statistic were used to determine the heterogeneity of the included studies. If P >0.1 and I2 <50%, it indicated that the heterogeneity was small and a fixed-effects model was selected for the analysis; if P ≤ 0.1 and I2 ≥ 50%, it indicated that there was a significant heterogeneity, and further judgment was needed to determine the source of the heterogeneity, and a random-effects model was selected for the analysis after eliminating the interference of significant clinical heterogeneity. Clinical and methodological heterogeneity was handled by subgroup analysis and sensitivity analysis, or descriptive analysis.