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.