Statistical analysis
All data in this trial were analyzed with the software SPSS V.22 (IBM). For categorical variables, analyses were computed using the χ-square or Fisher's exact test. For unpaired continuous quantities, either an independent-sample T-test (normal distribution) or an independent-sample Mann–Whitney U test (non-normal distribution) was used. In addition, the paired T-test (normal distribution) or Wilcoxon test (non-normal distribution) were performed for continuous variables.