Serum neutrophil gelatinase-associated lipocalin at inception of renal replacement therapy predicts survival in critically ill patients with acute kidney injury.
BACKGROUND
Neutrophil gelatinase-associated lipocalin (NGAL) is a promising novel biomarker that correlates with the severity and outcome of acute kidney injury (AKI). However, its prognostic utility during the late course of AKI, especially in patients that require renal replacement therapy (RRT) remains unknown. The aim of this study was to evaluate the predictive value of serum NGAL in patients with established AKI at inception of RRT in the intensive care unit (ICU).


METHODS
Serum NGAL (ELISA methodology) was measured in 109 critically ill patients with AKI at inception of RRT in 7 ICUs of a tertiary care university hospital. The primary outcome studied was 28-day mortality. Secondary outcome measures were ICU length of stay, ventilator-free days, and renal recovery at day 28.


RESULTS
There was a significant difference in serum NGAL between healthy subjects (median [interquartile range] 39.0 [37.5-42.75] ng/mL), critically ill patients with systemic inflammatory response syndrome (SIRS) (297 [184-490] ng/mL), and critically ill patients with sepsis (708 [365-1301] ng/mL; P < 0.0001), respectively. Multiple linear regression showed that NGAL levels were independently related to the severity of AKI and the extent of systemic inflammation. NGAL levels were higher in non-survivors (430 [303-942] ng/mL) compared to survivors (298 [159-506] ng/mL; P = 0.004). Consistently, Cox proportional hazards regression analysis identified NGAL as a strong independent predictor for 28-day survival (hazard ratio 1.6 (95% confidence interval [CI] 1.15 - 2.23), P = 0.005).


CONCLUSIONS
This is the first prospective evaluation of serum NGAL as an outcome-specific biomarker in critically ill patients at initiation of RRT. The results from this study indicate that serum NGAL is as an independent predictor of 28-day mortality in ICU patients with dialysis-dependent AKI.
Kümpers
Philipp
P
Department of Nephrology & Hypertension, Hannover Medical School, Carl-Neuberg Strasse 1, D-30625, Hannover, Germany. pkuempers@gmx.de
Hafer
Carsten
C
Lukasz
Alexander
A
Lichtinghagen
Ralf
R
Brand
Korbinian
K
Fliser
Danilo
D
Faulhaber-Walter
Robert
R
Kielstein
Jan T
JT
D058186:Acute Kidney Injury / Q000097:blood / Q000401:mortality / Q000628:therapy*; D000209:Acute-Phase Proteins; D000328:Adult; D015415:Biomarkers / Q000097:blood*; D016022:Case-Control Studies; D016638:Critical Illness; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D007902:Length of Stay; D000071068:Lipocalin-2; D054834:Lipocalins / Q000097:blood*; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011446:Prospective Studies; D011518:Proto-Oncogene Proteins / Q000097:blood*; D017582:Renal Replacement Therapy; D016019:Survival Analysis; D018746:Systemic Inflammatory Response Syndrome / Q000097:blood
D000209:Acute-Phase Proteins; D015415:Biomarkers; C489506:LCN2 protein, human; D000071068:Lipocalin-2; D054834:Lipocalins; D011518:Proto-Oncogene Proteins