2.5 Statistical Analysis
Continuous and categorical variables are presented as median (interquartile range [IQR]) and number (%), respectively. Comparisons between groups were performed using the Mann-Whitney U test, χ² test, or Fisher’s exact test where appropriate. Pearson’s correlations were employed to study the association between laboratory parameters. All statistical analyses were conducted using R software. Multivariate Cox regressions, log-rank tests, and Kaplan-Meier curves to plot the cumulative rates of death were implemented using theSurvival package in R software. The receiver operating characteristic (ROC) curve to assess the overall accuracy of a prognostic marker was applied by using the R package ROCR. AP -value < 0.05 was used to indicate statistical significance.