title: Diagnostic and prognostic value of serum cystatin C in critically ill children with acute kidney injury.
abstract: OBJECTIVE
  We aimed to evaluate the value of serum cystatin C for detection of acute kidney injury and pediatric Risk, Injury, Failure, Loss, End-Stage Renal Disease categories in critically ill children and to investigate whether serum cystatin C was associated with outcome.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  PICU of a tertiary-care university hospital.
  
  
  METHODS
  A heterogeneous population of critically ill children.
  
  
  METHODS
  None.
  
  
  RESULTS
  Blood and 24-hour urine samples were collected daily over the first 2 days after PICU admission for measurement of serum cystatin C, serum creatinine, and creatinine clearance. Acute kidney injury was classified by pediatric Risk, Injury, Failure, Loss, End-Stage Renal Disease criteria. One hundred twenty-two children were prospectively enrolled; 40 (32.8%) developed acute kidney injury. Serum cystatin C was higher in patients with acute kidney injury compared with those who did not develop acute kidney injury at PICU admission (median, 0.90 mg/L vs 0.51 mg/L) and on the first (1.12 mg/L vs 0.57 mg/L) and second PICU days (1.15 mg/L vs 0.58 mg/L). Serum creatinine was higher in acute kidney injury group only on the first (0.50 mg/dL vs 0.40 mg/dL) and second PICU days (0.60 mg/dL vs 0.40 mg/dL). Serum cystatin C was increasingly higher according to acute kidney injury severity (Failure > Injury > Risk). Area under the receiver operating characteristic curve of cystatin C for acute kidney injury detection was 0.89. Serum cystatin C greater than 0.70 mg/L was associated with longer length of PICU stay (adjusted hazard ratio, 1.64) and prolonged duration of mechanical ventilation (adjusted hazard ratio, 1.82).
  
  
  CONCLUSIONS
  Cystatin C is an early and accurate biomarker for acute kidney injury and pediatric Risk, Injury, Failure, Loss, End-Stage Renal Disease categories, and it is associated with adverse clinical outcomes in a heterogeneous population of critically ill children.
authors.affiliation: Division of Pediatric Critical Care, Department of Pediatrics, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil.
authors.forename: Leila C
authors.initials: LC
authors.lastname: Volpon
authors.forename: Edward K
authors.initials: EK
authors.lastname: Sugo
authors.forename: Ana P C P
authors.initials: AP
authors.lastname: Carlotti
mesh_terms: D058186:Acute Kidney Injury / Q000097:blood* / Q000175:diagnosis* / Q000628:therapy; D015415:Biomarkers; D002648:Child; D002675:Child, Preschool; D003404:Creatinine / Q000097:blood; D016638:Critical Illness; D055316:Cystatin C / Q000097:blood*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D015278:Intensive Care Units, Pediatric; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve; D012121:Respiration, Artificial / Q000706:statistics & numerical data; D012307:Risk Factors; D012720:Severity of Illness Index; D062606:Tertiary Care Centers
chemical_list: D015415:Biomarkers; D055316:Cystatin C; D003404:Creatinine