title: Acute changes in fluid status affect the incidence, associative clinical outcomes, and urine biomarker performance in premature infants with acute kidney injury.
abstract: BACKGROUND
  During the first postnatal weeks, infants have abrupt changes in fluid weight that alter serum creatinine (SCr) concentration, and possibly, the evaluation for acute kidney injury (AKI).
  
  
  METHODS
  We performed a prospective study on 122 premature infants to determine how fluid adjustment (FA) to SCr alters the incidence of AKI, demographics, outcomes, and performance of candidate urine biomarkers. FA-SCr values were estimated using changes in total body water (TBW) from birth; FA-SCR = SCr × [TBW + (current wt. - BW)]/ TBW; where TBW = 0.8 × wt in kg). SCr-AKI and FA-SCr AKI were defined if values increased by ≥ 0.3 mg/dl from previous lowest value.
  
  
  RESULTS
  AKI incidence was lower using the FA-SCr vs. SCr definition [(23/122 (18.8 %) vs. (34/122 (27.9 %); p < 0.05)], with concordance in 105/122 (86 %) and discordance in 17/122 (14 %). Discordant subjects tended to have similar demographics and outcomes to those who were negative by both definitions. Candidate urine AKI biomarkers performed better under the FA-SCr than SCr definition, especially on day 4 and days 12-14.
  
  
  CONCLUSIONS
  Adjusting SCr for acute change in fluid weight may help differentiate SCr rise from true change in renal function from acute concentration due to abrupt weight change.
authors.affiliation: Division of Pediatric Nephrology, Department of Pediatrics, University of Alabama at Birmingham, 1600 7th Ave S, Lowder 516, Birmingham, AL, 35233, USA. daskenazi@peds.uab.edu.
authors.forename: David
authors.initials: D
authors.lastname: Askenazi
authors.affiliation: Division of Pediatric Nephrology, Department of Pediatrics, University of Alabama at Birmingham, 1600 7th Ave S, Lowder 516, Birmingham, AL, 35233, USA.
authors.forename: Behtash
authors.initials: B
authors.lastname: Saeidi
authors.affiliation: Division of Pediatric Nephrology, Department of Pediatrics, University of Alabama at Birmingham, 1600 7th Ave S, Lowder 516, Birmingham, AL, 35233, USA.
authors.forename: Rajesh
authors.initials: R
authors.lastname: Koralkar
authors.affiliation: Division of Neonatology, Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: Namasivayam
authors.initials: N
authors.lastname: Ambalavanan
authors.affiliation: Department of Epidemiology, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: Russell L
authors.initials: RL
authors.lastname: Griffin
mesh_terms: D058186:Acute Kidney Injury / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology / Q000628:therapy; D000407:Alabama / Q000453:epidemiology; D015415:Biomarkers / Q000097:blood / Q000652:urine; D001724:Birth Weight; D003404:Creatinine / Q000097:blood; D005865:Gestational Age; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D007234:Infant, Premature; D019102:Infant, Very Low Birth Weight; D007668:Kidney / Q000503:physiopathology*; D008954:Models, Biological; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D013997:Time Factors; D016482:Urinalysis; D014882:Water-Electrolyte Balance; D014883:Water-Electrolyte Imbalance / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology / Q000628:therapy; D015431:Weight Loss
chemical_list: D015415:Biomarkers; D003404:Creatinine
keywords: Creatinine; Definitions; Fluid adjustment; NGAL; Urinary biomarkers; Very low birth weight