Statistical Analysis
Statistical analysis was performed with R software, version 3.6.0 (R Foundation for Statistical Computing, Vienna, Austria). Continuous data were expressed as the mean ± standard deviation for normally distributed variables or as medians (interquartile ranges) for non-normally distributed variables according to the Shapiro-Wilk test, and categoric data were expressed as count (percentage). Comparisons between continuous variables were made using Student’s t -test for normally distributed data or the Wilcoxon rank-sum test for non-normally distributed data based on the Shapiro-Wilk test. Categoric variables were compared using a chi-squared test. When ≥20% of expected counts were ≤5, however, Fisher’s exact test was used.