title: Comparative study of cystatin C and serum creatinine in the estimative of glomerular filtration rate in children.
abstract: BACKGROUND
  To compare estimated glomerular filtration rate (GFR) by Schwartz formula and cystatin C-derived formula in a large population of children with a large spectrum of renal disease.
  
  
  METHODS
  Serum creatinine, cystatin C and estimated GFR were determined in 273 children, 254 with renal disease, and a mean age of 10.0+/-4.4 y. Nineteen children were used as control, with a mean age of 8.5+/-4.2 y.
  
  
  RESULTS
  The children had nephrotic syndrome (16.5%), glomerulonephritis (11.4%), neurogenic bladder (11.4%), hydronephrosis (9.8%), asymptomatic hematuria (11%), chronic renal disease (5.9%) and other diseases (11%). Cystatin C, creatinine, Schwartz estimated GFR and cystatin C estimated GFR (mean+/-SD) were 1.30+/-1.03 mg/dl, 0.82+/-1.20 mg/l, 143+/-72 ml/min/1.73 m(2) and 88+/-36 ml/min/1.73 m(2), respectively. Although GFR estimated by creatinine and cystatin C had a significant correlation, the Bland-Altman analysis showed greater differences between GFR estimated by the 2 methods, with a mean difference of 50 ml/min. Besides, >50% of the patients with a reduced cystatin C estimated GFR had a normal GFR when analyzed by the Schwartz formula.
  
  
  CONCLUSIONS
  Our data shows that cystatin C-based GFR is more sensitive than previous study had demonstrated. It is important to perform studies in specific populations to determine the variability in GFR measurements.
authors.affiliation: Post-Graduate Program in Child and Adolescent Health, State University of Ceará, Fortaleza, Ceará, Brazil. vaniafc@superig.com.br
authors.forename: Vânia F
authors.initials: VF
authors.lastname: Cordeiro
authors.forename: Diana C S N
authors.initials: DC
authors.lastname: Pinheiro
authors.forename: Geraldo B
authors.initials: GB
authors.lastname: Silva
authors.forename: José Wellington O
authors.initials: JW
authors.lastname: Lima
authors.forename: Rosa M S
authors.initials: RM
authors.lastname: Mota
authors.forename: Alexandre B
authors.initials: AB
authors.lastname: Libório
authors.forename: Elizabeth F
authors.initials: EF
authors.lastname: Daher
mesh_terms: D000293:Adolescent; D001827:Body Height; D001835:Body Weight; D002648:Child; D002675:Child, Preschool; D003404:Creatinine / Q000097:blood*; D055316:Cystatin C; D015891:Cystatins / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007674:Kidney Diseases / Q000097:blood / Q000175:diagnosis* / Q000503:physiopathology; D007677:Kidney Function Tests; D008297:Male; D051437:Renal Insufficiency / Q000097:blood / Q000175:diagnosis* / Q000503:physiopathology
chemical_list: C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins; D003404:Creatinine