2.4 Statistical analysis
Continuous variables are presented as mean ± standard deviation or as median and interquartile range and were compared using the t-test or Wilcoxon rank-sum test based on the distribution. Categorical variables are expressed as number and percentage and were compared using the χ2 test. A p<0.05 was considered to indicate statistical significance. Multiple comparisons of continuous variables were performed using the Wilcoxon/Kruskal-Wallis test, whereas multiple comparisons of numerous variables were conducted with the χ2 test. If the test indicated a significant difference, we performed post-hoc analysis with adjustment using the Bonferroni method.