A Risk Stratified Assessment of Biomarker Based Acute Kidney Injury Phenotypes in Children

BACKGROUND: The functional acute kidney injury (AKI) diagnostic tests serum creatinine (SCr) and urine output are imprecise and make management challenging. Combining tubular injury biomarkers with functional markers reveal AKI phenotypes that may facilitate personalized care. However, when and in whom to obtain injury biomarkers remains unclear. METHODS: Prospective, observational study of patients admitted to a pediatric intensive care unit (PICU). Using the Renal Angina Index (RAI), subjects were screened for the presence (RAI+) or absence (RAI−) of renal angina 12 hours post-admission, and assigned an AKI phenotype using urinary NGAL (NGAL+: ≥150 ng/ml) and SCr (SCr+: ≥KDIGO Stage 1). Outcomes for each AKI phenotype were assessed and compared by RAI status. RESULTS: 200/247 (81%) subjects were RAI+. RAI+ subjects who were NGAL+ had higher risk of Day 3 AKI, renal replacement therapy use, and mortality, and fewer ventilator- and PICU-free days, compared to NGAL−, irrespective of Day 0 SCr. Similar findings were not demonstrated in RAI− subjects, though NGAL+/SCr+ was associated with fewer ventilator- and PICU-free days compared to NGAL−/SCr+. CONCLUSION: NGAL and SCr-based AKI phenotypes provide improved prognostic information in children with renal angina (RAI+) and/or with SCr elevation. These populations may be appropriate for targeted biomarker testing.