Statistical analysis
All statistics were analyzed using SPSS software version 22.0 (IBM Corp., Armonk, NY, USA). Data were presented as means with standard deviations (SDs) or medians with interquartile ranges (IQRs) and 25th-75th percentiles. The Mann-Whitney U test was used to compare nonparametric variables and Student’s t -test was used for parametric data. The paired sample t -test and repeated measure ANOVA, followed by the post hoc Tukey test, were used to evaluate changes of variables. Values of p <0.05 were considered statistically significant.