Statistical analysis
Statistical analyses were performed using Stata (version 12.0; StataCorp, United States). Graphics were generated with GraphPad Prism 8 (GraphPad Software, United States). Qualitative variables are reported as the total number and percentage and were compared using chi-squared tests. Quantitative variables are reported as the mean with standard deviation or median with range and were compared using Student’s t-test with Welch’s correction (normally distributed) or the Mann–Whitney U test and Kruskal–Wallis test (nonnormally distributed). Spearman’s correlation coefficient (r) is reported for correlations. To test for normality distribution, we applied the D’Agostino-Pearson test. Values were considered significant at p<0.05.