Statistical Analysis:
SPSS 22.0 for Mac (IBM SPSS Statistics) was used for statistical
analysis. Continuous variables were reported as the mean +/− standard
deviation or median (interquartile range) (IQR). Categorical variables
were reported as the absolute frequency and as a percentage. Student’st -test was applied for continuous data with equal or unequal
variances. The Mann-Whitney U test was applied for continuous data that
were not normally distributed. Pearson’s \(\chi\)2 and Fisher’s
exact tests were used for categorical data. All meaningful variables
were included in a multiple logistic regression analysis. Logistic
regression analysis was repeated using variables that were significant
in the previous analysis 15. Accuracy was measured by
the area under the receiver operating characteristic (ROC) curve
analysis. p < 0.05 was considered to be statistically
significant.