Statistical analysis
For statistical analysis, we employed SPSS version 22.0. We reported continuous variables and mean standard deviations with a 95% confidence interval. We applied the Wilcoxon Mann–Whitney U test for numerical variables not normally distributed or anisotropic. We compared categorical variables using the Pearson χ2 test or Fisher's exact test. We considered p-values less than 0.05 to be statistically significant.