Compared to the derivation cohort, the test cohort had a higher proportion of Caucasians and a greater proportion with selleck Dorsomorphin no causative organism isolated. The test cohort also had a lower proportion with no reported race and a lower proportion with gram-positive bacteria, compared to the derivation cohort. The test and derivation cohorts were otherwise not statistically different. Within the test cohort, there were no significant differences between survivors and non-survivors, except for the median PRISM scores. The mean and median times to death in the test cohort non-survivors were 9.9 �� SD 11.2 and 4 (IQR 2 to 16) days, respectively. A complete list of comorbidities for the survivors in the test cohort is provided in Additional File 3. A list of causative organisms for the test cohort is provided in Additional File 4.

Table 3Demographics and clinical characteristics of the test cohortThe classification of the test cohort participants according to the decision tree is shown in Additional File 5. Seventy-seven patients were classified as low risk (nodes 5 and 8), while 58 were classified as high risk (nodes 2, 4, and 10). Among the low-risk participants, the mortality rate was 2.6%, while among the high-risk participants the mortality rate was 27.6%. The diagnostic test characteristics of the decision tree in the test cohort are shown in Table Table22.Secondary considerationsThe classification tree was updated using all 355 participants in the combined derivation and test cohorts. The model parameters, pruning criteria, and the command file for reproducing the updated classification tree are provided in Additional File 6.

All 12 candidate biomarkers, as well as age and gender were considered in the updating process. The updated decision tree is shown in Figure Figure2.2. Maximum accuracy was achieved with three of the same stratification biomarkers (CCL3, HSPA1B, and IL8), while the importance of ELA2 and LCN2 were superseded by GZMB and MMP8. Age also added to the predictive capacity of the updated tree (nodes 13 and 14). There were three low-risk terminal nodes (0.0 to 2.5% risk of death; nodes 7, 11, and 14) and five high-risk terminal nodes (18.2 to 62.5% risk of death; nodes 4, 8, 10, 12, and 13). Of the 236 participants classified as low risk, 233 survived (98.7%) and 3 had died (1.3%) by 28 days. Of the 119 participants classified as high risk, 38 had died (31.9%) by 28 days. The diagnostic test characteristics of the updated decision tree are shown in Table Table22.Figure 2Classification tree from the updated model based on the combined derivation and test cohorts (n = 355). The classification tree consists of six biomarker-based decision rules, one age-based decision rule, AV-951 and fourteen daughter nodes. The classification …