Risk of poor outcomes with novel and traditional biomarkers at clinical AKI diagnosis.
OBJECTIVE
Studies have evaluated acute kidney injury (AKI) using biomarkers in various settings, but their prognostic utility within current practice is unclear. Thus, we sought to determine the prognostic utility of newer biomarkers or traditional markers (fractional excretion of sodium [FeNa] and urea [FeUrea] and microscopy) over clinical assessment alone.


METHODS
This is a prospective cohort study of adults on the first day of meeting AKI criteria. We measured urine concentrations of neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), and IL-18 and determined FeNa, FeUrea, and microscopy score for casts and tubular cells. Primary outcome was worsened AKI stage from enrollment to peak serum creatinine or in-hospital death.


RESULTS
In 249 recipients, 57% were ≥65 years old, 48% were from intensive care, and mean baseline GFR was 69 ± 30 ml/min per 1.73 m(2). AKI was considered prerenal in 164 (66%), acute tubular necrosis (ATN) in 51 (20%), and "other" in 34 (14%). All mean protein biomarker concentrations, FeNa, FeUrea, and microscopy scores were statistically different between prerenal and ATN. Seventy-two patients (29%) developed the primary outcome. There was an approximate three-fold increase in adjusted risk for the outcome for upper versus lower values of NGAL, KIM-1, IL-18, and microscopy score (P values <0.05). Net reclassification improved after adding these to baseline clinical assessment. FeNa and FeUrea were not useful.


CONCLUSIONS
On the first day of AKI, urine protein biomarkers and microscopy significantly improve upon clinical determination of prognosis, indicating their potential utility in current practice.
Department of Medicine, Section of Nephrology, Yale University School of Medicine, New Haven, Connecticut, USA.
Isaac E
IE
Hall
Steven G
SG
Coca
Mark A
MA
Perazella
Umo U
UU
Eko
Randy L
RL
Luciano
Patricia R
PR
Peter
Won K
WK
Han
Chirag R
CR
Parikh
D058186:Acute Kidney Injury / Q000145:classification / Q000175:diagnosis* / Q000652:urine; D000209:Acute-Phase Proteins / Q000652:urine; D000368:Aged; D015415:Biomarkers / Q000652:urine; D015331:Cohort Studies; D003404:Creatinine / Q000097:blood; D005260:Female; D000072596:Hepatitis A Virus Cellular Receptor 1; D006801:Humans; D020382:Interleukin-18 / Q000652:urine; D000071068:Lipocalin-2; D054834:Lipocalins / Q000652:urine; D008297:Male; D008562:Membrane Glycoproteins / Q000652:urine; D011379:Prognosis; D011446:Prospective Studies; D011518:Proto-Oncogene Proteins / Q000652:urine; D011991:Receptors, Virus; D012964:Sodium / Q000652:urine; D014508:Urea / Q000652:urine
D000209:Acute-Phase Proteins; D015415:Biomarkers; C491143:HAVCR1 protein, human; D000072596:Hepatitis A Virus Cellular Receptor 1; D020382:Interleukin-18; C489506:LCN2 protein, human; D000071068:Lipocalin-2; D054834:Lipocalins; D008562:Membrane Glycoproteins; D011518:Proto-Oncogene Proteins; D011991:Receptors, Virus; D014508:Urea; D012964:Sodium; D003404:Creatinine