Statistical analyses
All statistical analyses were performed on IBM SPSS version 24.0 (IBM Co., Armonk, NY, USA) at an alpha level of 0.05. Data were summarised using mean (SD) for continuous variables and frequency (percentage) for discrete variables. Comparison of baseline categorical variables among the different treatment groups (PE plus MCE, PE, MCE) was conducted using the chi-square test (for cells count > 5) or Fisher's exact test (for cells count < 5) while one-way between-subjects analysis of variance (ANOVA) was used for continuous variables.