Statistical analysis
SPSS software (version 22.0) was used to perform the statistical analyses. Categorical variables were reported as frequencies and percentages, and were analyzed using χ2 tests. Continuous variables were analyzed using the Student’s t test or Mann-Whitney U test, where appropriate. The receiver operating characteristic (ROC) curve analysis was utilized to determine the optimal cut-off values of inflammatory predictors with MedCalc 17.6. The area under the ROC curve (AUC) was used to compare prognostic factors. The multivariate logistic regression analysis was performed on the factors that were shown to be significant on univariate logistic analysis. Odds ratio (OR) and 95% confidence intervals (CIs) were utilized to evaluate relative risk. All tests were two-sided and P<0.05 was considered to indicate a statistically significant different.