Quantitative results were expressed as either the median or the mean ± standard deviation (SD). All statistical analyses were performed in the SPSS software package (version 19.0, IBM Corporation, Armonk, NY), with the exception of ROC curve analyses that were performed in the MedCalc software package (version 11.4.2.0, MedCalc Software bvba, Belgium). Continuous variables were compared with Student's t tests or Mann–Whitney U tests. Categorical variables were compared with Spearman rank correlation tests. ROC curves were plotted for EPIC, Balthazar, BISAP, and SIRS scores to assess their ability to predict organ failure. The AUC and 95% confidence interval (CI) for each of these scoring systems was calculated, and the AUCs were compared using z tests. An AUC value of 0.50 to 0.69 was defined as low accuracy, 0.70 to 0.90 was defined as moderate accuracy, and > 0.90 was defined as good accuracy. Differences with a P value < 0.05 were considered statistically significant. Correlational analyses between EPIC scores and severity of organ failure, between EPIC score and number of failed organs, and between EPIC score and outcome parameters were performed with R × C contingency table tests (McNemar test and Kappa test) and Spearman analyses. A Spearman correlation coefficient with an absolute value in the range of 0.090 to 0.099 was defined as indicating no correlation, those in the range of 0.10 to 0.29 were defined as indicating a weak correlation, those in the range of 0.30 to 0.49 were defined as indicating a moderate correlation, and those in the 0.50 to 1.0 range were defined as indicating a strong correlation.