Statistical analysis
EZR version 1.40 (Saitama Medical Center, Jichi Medical University, Saitama, Japan) was used for the statistical analysis, which is a graphical user interface for R (The R Foundation for Statistical Computing, Vienna, Austria). The continuous variables were expressed as the mean ± standard deviation. Two-group comparisons were analyzed using a Student’s t-test or Mann-Whitney U test. Categorical variables were expressed as the number (percentage), which was compared using a Fisher’s exact test or chi-squared test. In the multivariate analysis, the age, sex, and clinical factors that could influence ERATs were included.