Statistical analysis
Data are expressed as scatter dot plots with medians or as box and whisker plots showing the smallest observation, lower quartile, median, upper quartile, and largest observation or as medians with interquartile ranges. Mann-Whitney U test or Kruskal-Wallis test followed by Dunn’s multiple comparisons post test was performed for statistical analysis. Non-parametric Spearman’s Rank Correlation Coefficient was used to analyze correlations. To determine the discriminative power of human soluble CXCL16 for 28-day mortality, receiver-operating characteristic (ROC) curves were constructed and the area under the curve (AUC) was determined with its 95% confidence interval (CI). For comparisons of AUCs, the Z-test formula was used. Binary logistic regression analysis was performed to determine the independent predictors of 28-day mortality. For survival studies, Kaplan–Meier analyses followed by log-rank tests were performed. All analyses were done with GraphPad Prism version 5.01 (GraphPad Software, San Diego, CA). p values less than 0.05 were considered statistically significant.