Statistical Analysis
The normality of the distribution of continuous variables was tested
using the Shapiro-Wilk test. Student’s t-test (for normal data) or the
Mann-Whitney U test (for non-normal data) were used to compare two
independent groups. The Chi-square test was used to investigate the
relationship between categorical variables. Receiver operating
characteristics (ROC) curve analysis was performed to determine the
diagnostic values of some numerical measurements.
Discrimination of the model was graded according to the area under the
ROC curve, as follows: 0.5-0.6 = fail discrimination, 0.6-0.7 = poor
discrimination, 0.7-0.8 = acceptable discrimination, 0.8-0.9 = good
discrimination, 0.9-1 = excellent discrimination. Statistical analysis
was performed using the SPSS for Windows version 24.0 software and
P-values <0.05 were accepted as statistically significant.