Estimation of the optimal surrogate based on a randomized trial.

A common scientific problem is to determine a surrogate outcome for a long-term outcome so that future randomized studies can restrict themselves to only collecting the surrogate outcome. We consider the setting that we observe n independent and identically distributed observations of a random variable consisting of baseline covariates, a treatment, a vector of candidate surrogate outcomes at an intermediate time point, and the final outcome of interest at a final time point. We assume the treatment is randomized, conditional on the baseline covariates.

A Two-Biomarker Model Predicts Mortality in the Critically Ill with Sepsis.

Rationale: Improving the prospective identification of patients with systemic inflammatory response syndrome (SIRS) and sepsis at low risk for organ dysfunction and death is a major clinical challenge.

Objectives: To develop and validate a multibiomarker-based prediction model for 28-day mortality in critically ill patients with SIRS and sepsis.

Methods: A derivation cohort (n = 888) and internal test cohort (n = 278) were taken from a prospective study of critically ill intensive care unit (ICU) patients meeting two of four SIRS criteria at an academic medical center for whom plasma was obtained within 24 hours.

Association of markers of endothelial dysregulation Ang1 and Ang2 with acute kidney injury in critically ill patients.

Background: The role of endothelial dysregulation with acute kidney injury (AKI) in critically ill patients is unclear.

Methods: We retrospectively assessed the associations of AKI with biomarkers of endothelial function and inflammation among 948 subjects admitted to the intensive care unit (ICU) at Harborview Medical Center (Seattle, WA, USA). From plasma obtained within 24 h of enrollment, we measured angiopoietin (Ang)-1 and Ang-2 alongside biomarkers of inflammation, including interleukin (IL)-6, IL-17 and granulocyte colony-stimulating factor.

Biomarkers of Endothelial Activation Are Associated with Poor Outcome in Critical Illness.

Background: Endothelial activation plays a role in organ dysfunction in the systemic inflammatory response syndrome (SIRS). Angiopoietin-1 (Ang-1) promotes vascular quiescence while angiopoietin-2 (Ang-2) mediates microvascular leak. Circulating levels of Ang-1 and Ang-2 in patients with SIRS could provide insight on risks for organ dysfunction and death distinct from inflammatory proteins.