title: Baseline values of candidate urine acute kidney injury biomarkers vary by gestational age in premature infants.
abstract: Acute kidney injury (AKI) is common in premature infants and is associated with poor outcomes. Novel biomarkers can detect AKI promptly. Because premature infants are born with underdeveloped kidneys, baseline biomarker values may differ. We describe baseline values of urinary neutrophil gelatinase-associated lipocalin (NGAL), IL-18, kidney injury molecule-1 (KIM-1), osteopontin (OPN), beta-2 microglobulin (B2mG), and Cystatin-C (Cys-C). Next, we test the hypothesis that these biomarkers are inversely related to GA. Candidate markers were compared according to GA categories in 123 infants. Mixed linear regression models were performed to determine the independent association between demographics/interventions and baseline biomarker values. We found that urine NGAL, KIM-1, Cys-C, and B2mG decreased with increasing GA. With correction for urine creatinine (cr), these markers and OPN/cr decreased with increasing GA. IL-18 (with or without correction for urine creatinine) did not differ across GA categories. Controlling for other potential clinical and demographic confounders with regression analysis shows that NGAL/cr, OPN/cr, and B2mG/cr are independently associated with GA. We conclude that urine values of candidate AKI biomarkers are higher in the most premature infants. These findings should be considered when designing and analyzing biomarker studies in newborn with AKI.
authors.affiliation: Department of Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama 35233, USA. daskenazi@peds.uab.edu
authors.forename: David J
authors.initials: DJ
authors.lastname: Askenazi
authors.forename: Rajesh
authors.initials: R
authors.lastname: Koralkar
authors.forename: Emily B
authors.initials: EB
authors.lastname: Levitan
authors.forename: Stuart L
authors.initials: SL
authors.lastname: Goldstein
authors.forename: Prasad
authors.initials: P
authors.lastname: Devarajan
authors.forename: Srikrishna
authors.initials: S
authors.lastname: Khandrika
authors.forename: Ravindra L
authors.initials: RL
authors.lastname: Mehta
authors.forename: Namasivayam
authors.initials: N
authors.lastname: Ambalavanan
mesh_terms: D058186:Acute Kidney Injury / Q000175:diagnosis / Q000652:urine*; D015415:Biomarkers / Q000652:urine*; D003404:Creatinine / Q000097:blood / Q000652:urine; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn / Q000652:urine*; D007234:Infant, Premature / Q000652:urine*; D019102:Infant, Very Low Birth Weight / Q000652:urine*; D007677:Kidney Function Tests; D011247:Pregnancy
chemical_list: D015415:Biomarkers; D003404:Creatinine