For statistical analysis, we used IBM SPSS Statistics version 21 (IBM, Armonk, NY, USA). Based on the distribution of values, continuous data were expressed as mean ±  standard deviation or as  median and interquartile range (IQR). Depending on the number of groups and data distribution, we applied the t test, the Mann–Whitney U test or the Kruskal–Wallis test (followed by Dunn–Bonferroni post hoc test). All reported p values were adjusted for multiple comparisons. We adopted the Chi-square test for categorical variables. Differences were considered statistically significant at p < 0.05.