All statistical analyses were performed using SPSS 21.0 statistical software. Measurement data were presented by mean ± standard deviation (AV ± SD). Unpaired Student's t-test for parametric data or Mann-Whitney rank sum test for nonparametric data were applied to analyze mean value between two groups. Chi-square tests were applied to determine count data expressed in n (%). In all cases, p < 0.05 was considered statistically significant.