Statistical analysis
The data were analyzed using SPSS 21.0 software for Windows (SPSS, Inc. IBM, NY, USA). Data are presented as the mean ± standard deviation (SD) or as the median (minimal, maximal), according to data (determined by the Shapiro-Wilk test), while categorical variables are presented as frequency (percentages) and were analyzed by Pearson’s chi-square test and Fisher’s exact test as appropriate. The crude significance of within-group and intergroup differences was tested by Student’s t test, paired-samples t test, the Wilcoxon test, or the Mann–Whitney U test, as appropriate. Values of 