Statistical Analysis
ADVERSE EVENT
We calculated that a sample of 60 participants per group would provide at least 90% power with a .05 2-sided significance. According to the conservative principle in the sample size calculation, the decrease in the VAS score was assumed to be 5.24 in the placebo group and 6.48 in the mifepristone group (eAppendix 3 in Efficacy was analyzed in the full-analysis set (FAS) and per-protocol set (PPS). The FAS population included eligible participants who were randomized, and patients without any valid data at baseline were excluded. The PPS population was defined as all randomized patients who received at least 1 dose of the investigational product and had valid VAS assessments at and after baseline. The primary analysis was performed. Missing values were excluded from the analysis without missing value imputation. Furthermore, a sensitivity analysis of the primary efficacy outcome was performed to assess the effect of discontinuation under different missing data mechanisms. Missing values for continuous outcomes were handled using a multiple imputation method with fully conditional specification. Trial group, age, and the results of other visit time points, such as VAS score, were used as covariates, and 50 imputed data sets were generated. After multiple imputation was been performed, the next steps were to apply statistical tests in each imputed data set and to pool the results to obtain summary estimates. Adverse events were analyzed in the safety set, defined as participants who received at least 1 dose of the intervention or placebo drug.As the primary end point, the change in VAS score from baseline to week 12 between groups was compared using the Wilcoxon test. The Pearson χ