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.