2.3. Statistical analysis

The minimum sample size was calculated by PASS version 11.0.10 program (NCSS, LLC, Kaysville, UT, USA). IBM SPSS 20.0 (SPSS Inc., Chicago, IL, USA) was used for statistical analysis. Kolmogorov‐Smirnow test was selected to assess the normality of calculated parameters. The data with normal and skewed distributions were, respectively, showed as mean ± standard deviation (SD) and median (25% quartile‐75% quartile). Student's t test was selected to assess normally distributed parameter; otherwise, Mann‐Whitney U test was performed. The chi‐square test was used for categorical variables. Receiver‐operating characteristics (ROC) curve analysis was performed to identify cutoff values of these biomarkers, and the differences in the area under the curve (AUC) were analyzed using MedCalc version 15.0 (MedCalc Software, Mariakerke, Belgium). A P‐value <0.05 was considered statistically significant.