Statistical Analysis
For continuous variables, data are expressed as the mean value
SD unless otherwise specified. Comparisons were made between
continuous variables by using the Student’s t test. Categorical
variables are expressed as a percentage. For categorical variables,
comparisons between groups were made by using the 2
test. The Fisher’s exact test and Wilcoxon rank sum were applied
to nonnormally distributed data. All statistical tests were 2-tailed,
and results were considered to be significant at P values .05.