4. Statistical analysis
The study data were subjected to statistical analysis using the SPSS
version 20.0 (SPSS Inc, Chicago, IL). All data were expressed as
numbers, percentiles, mean, median, and standard deviation (SD). Student
t test was used for univariate analysis of the difference between
groups. Mann-Whitney U test was performed as the non-parametric test.
The receiving operating characteristic (ROC) curve and the value of area
under the curve (AUC) were used to analyze the accuracy of different
parameters to predict AL and the best cut-off point was selected.
p<0.05 was considered statistically significant.