Novel biomarkers may improve our ability to predict which patients with chronic 
kidney disease (CKD) are at higher risk for progressive loss of renal function. 
Here, we assessed the performance of urine neutrophil gelatinase-associated 
lipocalin (NGAL) for outcome prediction in a diverse cohort of 3386 patients 
with CKD in the Chronic Renal Insufficiency Cohort study. In this cohort, the 
baseline mean estimated glomerular filtration rate (eGFR) was 42.4 ml/min per 
1.73 m(2), the median 24-h urine protein was 0.2 g/day, and the median urine 
NGAL concentration was 17.2 ng/ml. Over an average follow-up of 3.2 years, there 
were 689 cases in which the eGFR was decreased by half or incident end-stage 
renal disease developed. Even after accounting for eGFR, proteinuria, and other 
known CKD progression risk factors, urine NGAL remained a significant 
independent risk factor (Cox model hazard ratio 1.70 highest to lowest 
quartile). The association between baseline urine NGAL levels and risk of CKD 
progression was strongest in the first 2 years of biomarker measurement. Within 
this time frame, adding urine NGAL to a model that included eGFR, proteinuria, 
and other CKD progression risk factors led to net reclassification improvement 
of 24.7%, but the C-statistic remained nearly identical. Thus, while urine NGAL 
was an independent risk factor of progression among patients with established 
CKD of diverse etiology, it did not substantially improve prediction of outcome 
events.