Plasma neutrophil gelatinase-associated lipocalin at intensive care unit admission as a predictor of acute kidney injury progression

Background. Acute kidney injury (AKI) is a common complication in patients during intensive care unit (ICU) admission. AKI is defined as an increase in serum creatinine (SCr) and/or a reduction in urine output. SCr is a marker of renal function with several limitations, which led to the search for biomarkers for earlier AKI detection. Our aim was to study the predictive value of plasma neutrophil gelatinase-associated lipocalin (NGAL) at admission as a biomarker for AKI progression during the first 48h of ICU admission in an unselected, heterogeneous ICU patient population. Methods. We conducted a prospective observational study in an academic tertiary referral ICU population. We recorded AKI progression in all ICU patients during the first 48h of ICU admission in a 6-week period. Plasma NGAL was measured at admission but levels were not reported to the attending clinicians. As possible predictors of AKI progression, pre-existing AKI risk factors were recorded. We examined the association of clinical parameters and plasma NGAL levels at ICU admission with the incidence and progression of AKI within the first 48h of the ICU stay. Results. A total of 361 patients were included. Patients without AKI progression during the first 48h of ICU admission had median NGAL levels at admission of 115 ng/mL [interquartile range (IQR) 81-201]. Patients with AKI progression during the first 48h of ICU admission had median NGAL levels at admission of 156 ng/mL (IQR 97-267). To predict AKI progression, a multivariant model with age, sex, diabetes mellitus, body mass index, admission type, Acute Physiology and Chronic Health Evaluation score and SCr at admission had an area under the receiver operating characteristics (ROC) curve of 0.765. Adding NGAL to this model showed a small increase in the area under the ROC curve to 0.783 (95% confidence interval 0.714-0.853). Conclusions. NGAL levels at admission were higher in patients with progression of AKI during the first 48h of ICU admission, but adding NGAL levels at admission to a model predicting this AKI progression showed no significant additive value