Figure 1. Classification of the test cohort subjects according to the updated version of PERSEVERE.

The classification tree consists of 6 biomarker-based decision rules, 1 age-based decision rule, 14 daughter nodes, and 8 terminal nodes. The classification tree includes C-C chemokine ligand 3 (CCL3), heat shock protein 70 kDa 1B (HSPA1B), interleukin-8 (IL8), granzyme B (GZMB), and matrix metalloproteinase-8 (MMP8). Each node provides the total number of subjects in the node, the biomarker serum concentration- or age-based decision rule, and the number of survivors and non-survivors with the respective rates. For consistency, the serum concentrations of all stratification biomarkers are provided in pg/ml. The terminal nodes are numbered TN1 through TN8, and each terminal node provides the actual mortality and survival rates for the respective test cohort subjects, as well as the respective mortality probability of the updated decision tree, in parentheses. Terminal nodes 2, 4, and 7 are low risk terminal nodes (mortality probability 0.000 to 0.025), terminal nodes 1, 3, and 5 are intermediate risk terminal nodes (mortality probability 0.182 to 0.267), and terminal nodes 6 and 8 are high-risk terminal nodes (mortality probability 0.472 to 0.625). To calculate the diagnostic test characteristics, all subjects in the low risk terminal nodes (n = 123) were classified as predicted survivors, whereas all subjects in the intermediate and high risk terminal nodes (n = 59) were classified as predicted non-survivors.