Statistical analysis was carried out using the SPSS 13.0 software package (SPSS Inc, Chicago, IL, USA). Kolmogorov-Smirnov tests were used to test the normality of data distribution. Data were expressed as arithmetic means and standard deviations. Chi-square test was used to compare the categorical variables between groups. Independent sample T-test and Mann-Whitney U tests were used respectively between groups in normally and abnormally distributed continuous variables. Paired t-test and Wilcoxon signed-rank tests were used to analyze changes within each group. Two-sided p value <0.05 was considered statistically significant.