Figure 1. An integrative systems survey of sepsis survival and death.

(A) CONSORT flow chart of patient enrollment and selection. Patients presenting to emergency departments with suspected community-acquired sepsis (acute infection and ≥2 SIRS criteria) were grouped according to final adjudication (sepsis or SIRS, no infection), day 3 clinical course (septic shock, severe sepsis, and uncomplicated sepsis) and outcome at day 28 (survival or death). Groups were defined by the most severe stage of sepsis attained. A subset of cases were chosen for the derivation study based upon planned number (n=30) of patients per subgroup and enriched for etiologic agents and controlling for attributes defined by the sepsis nonsurvivor group. The validation group had limited number of sepsis nonsurvivors. ¹ One sepsis nonsurvivor initially refused phlebotomy at t₀, yet later agreed at t₂₄. The sample was utilized to maximize validation predictive modeling studies. No non-infected SIRS validation samples were selected because predictive modeling was not successful during derivation. (B) Experimental design. MS-based metabolome and proteome analysis was performed on plasma samples obtained at t₀ and t₂₄ from 150 matched derivation subjects. Validation of metabolome findings was sought by semi-quantitative MS in an independent cohort comprising all remaining sepsis nonsurvivors and a matched group of sepsis survivors at t₀ and t₂₄ (n=52). Following molecular integration and analysis, predictive models were developed that were representative of the clinical and molecular findings. A top model utilizing semi-quantitative metabolomics clinical measures was trained at t₀, and then tested against the derivation t₂₄ group, validation groups (Vt₀, Vt₂₄) and an independent validation (RoCI) cohort. The utility of the predictive models was further tested by clinical measures and targeted, quantitative assays of butyroylcarnitine, 2-methylbytyroylcarnitine, hexanoylcarnitine, cis-4-decenoylcarnitine, 1-arachidonoyl-glycerophosphocholine (GPC), 1-linoleoyl-GPC, pseudouridine, 3-(4-hydroxyphenyl)lactate (HPLA), 4-methyl-2-oxopentanoate, 3-methoxytyrosine and N-acetylthreonine of 382 samples, four samples were not included in a subset of metabolites due to limited serum volume. Tests included logistic regression of the top model derived by semi-quantitative results and Support Vector Machine (SVM) analysis of the top model.