Early Laboratory Predictors of Sepsis-Associated Acute Kidney Injury and Short-Term Clinical Outcomes in Emergency Department Patients

Abstract

Objective: The objective of this study was to identify early laboratory and microbiological markers for SA-AKI and 28-day mortality in emergency department patients who were admitted with sepsis, focusing on the pathology and microbiology parameters.

Material and Methods: Prospective observational cohort study in the tertiary care ED. Patients of age who fulfilled the Sepsis-3 criteria were recruited as adults. Blood and urine samples were taken within 6 hours of triage. Routine biochemistry, novel biomarkers (Neutrophil Gelatinase-Associated Lipocalin [NGAL], Kidney Injury Molecule-1 [KIM-1] and Interleukin-6 [IL-6]), and comprehensive microbiological analysis (two sets of blood culture time to positivity, MALDI-TOF MS identification) were measured.

Results: 168 of the 420 enrolled patients (40%) had sepsis-associated acute kidney injury (SA-AKI). At baseline, NGAL, KIM-1, IL-6 and the ratio of Neutrophils to Lymphocytes (NLR) were all significantly higher in the SA-AKI patients, as was the time to blood culture positivity (TTP). NGAL (OR 4.12), IL-6 (OR 2.85), TTP < 12 hours (OR 3.45), and Gram-negative bacteremia (OR 2.10) were all independent risk factors for SA-AKI (all p < 0.05). Overall, the biomarker panel had an AUC of 0.91 for SA-AKI prediction. There was a strong association between shorter TTP and higher levels of IL-6, and both with 28-day mortality.

Conclusion: Early integrated laboratory and microbiological profiling using NGAL, IL-6 and blood culture TTP enables very accurate and rapid prediction of SA-AKI and early mortality in ED sepsis patients and enables prompt targeted intervention.