title: Microalbuminuria and hyperfiltration in subjects with nephro-urological disorders.
abstract: BACKGROUND
  Microalbuminuria (MA) has been shown to be an early biomarker of renal damage. It is postulated that MA is the early result of hyperfiltration, which could evolve into glomerular sclerosis and renal failure if hyperfiltration is left untreated. We hypothesized that MA is a good indicator of hyperfiltration in children with kidney disorders, obviating the need to calculate the filtration fraction (FF).
  
  
  METHODS
  A total of 155 children or young adults were prospectively included [42 single kidney (SK), 61 vesico-ureteral reflux, 23 obstructive uropathies, 29 other kidney diseases]. We measured inulin, para-aminohippuric acid clearances, FF and MA. Prediction of hyperfiltration was explored by studying the association between the FF and other variables such as urinary albumin (Alb), urinary albumin-creatinine ratio (ACR) and creatinine clearance.
  
  
  RESULTS
  A significant but weak association between urinary Alb or ACR and FF was found in subjects with an SK (Spearman correlation coefficients 0.32 and 0.19, respectively). Multivariate analysis also showed that urinary Alb and ACR significantly predict FF only in subjects with an SK (r(2) = 0.17, P = 0.01 and r(2) = 0.13, P = 0.02, respectively). This holds true only in subjects with an SK and inulin clearance >90 mL/min/1.73 m(2) (r(2) = 0.41, P < 0.001). There was no association between creatinine clearance and FF.
  
  
  CONCLUSIONS
  MA is not associated with FF in our subjects with nephro-urological disorders, except in those with an SK, where the association is weak, indicating that MA is due to other mechanisms than high FF and cannot predict hyperfiltration in such groups.
authors.affiliation: Department of Pediatrics, Division of Pediatric Nephrology, University Hospital, Lausanne, Switzerland. fcachat@hotmail.com
authors.forename: Francois
authors.initials: F
authors.lastname: Cachat
authors.forename: Christophe
authors.initials: C
authors.lastname: Combescure
authors.forename: Hassib
authors.initials: H
authors.lastname: Chehade
authors.forename: Gregory
authors.initials: G
authors.lastname: Zeier
authors.forename: Dolores
authors.initials: D
authors.lastname: Mosig
authors.forename: Blaise
authors.initials: B
authors.lastname: Meyrat
authors.forename: Peter
authors.initials: P
authors.lastname: Frey
authors.forename: Eric
authors.initials: E
authors.lastname: Girardin
mesh_terms: D000293:Adolescent; D000419:Albuminuria / Q000503:physiopathology* / Q000652:urine; D015415:Biomarkers / Q000652:urine; D002648:Child; D003404:Creatinine / Q000652:urine; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology*; D006801:Humans; D007668:Kidney / Q000503:physiopathology*; D007674:Kidney Diseases / Q000503:physiopathology* / Q000652:urine; D008297:Male; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D011446:Prospective Studies; D014524:Urethral Obstruction / Q000503:physiopathology* / Q000652:urine; D014718:Vesico-Ureteral Reflux / Q000503:physiopathology* / Q000652:urine
chemical_list: D015415:Biomarkers; D003404:Creatinine