title: Effect of clinical variables and immunosuppression on serum cystatin C and beta-trace protein in kidney transplant recipients.
abstract: BACKGROUND
  Cystatin C and beta-trace protein (BTP) are low-molecular-weight proteins that have generated interest as alternative endogenous markers of glomerular filtration rate (GFR). Studies examining the effect of demographic, biometric, clinical, and biochemical variables on cystatin C levels have yielded conflicting results, perhaps because of the reliance on inferior methods of GFR determination. The aim of this study is to examine the independent effect of various clinical parameters on serum concentrations of creatinine, cystatin C, and BTP in kidney transplant recipients.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  207 kidney transplant recipients with stable kidney function.
  
  
  METHODS
  GFR, age, race, sex, body mass index, albumin level, proteinuria, smoking status, prednisone, and calcineurin inhibitor and mycophenolate mofetil use.
  
  
  METHODS
  Multiple linear regression analysis was used to examine the relationship between predictor variables and cystatin C, BTP, and creatinine levels. GFR was measured by using technetium 99m-radiolabeled diethylenetriaminepentaacetic acid clearance.
  
  
  RESULTS
  After adjusting for GFR, cystatin C and BTP levels were significantly lower in women compared with men. Greater albumin concentration was associated with significantly lower cystatin C and BTP concentrations. There was a statistically significant, but clinically small, association between body mass index and cystatin C level, but no association between the other demographic variables or medications analyzed.
  
  
  CONCLUSIONS
  Predominantly white population; results may not be applicable to other racial groups.
  
  
  CONCLUSIONS
  Important nonrenal factors can influence BTP and cystatin C concentrations and need to be considered when interpreting BTP and cystatin C values in kidney transplant patients.
authors.affiliation: Department of Medicine, Division of Nephrology, Queen's University, Kingston, Canada.
authors.forename: Christine A
authors.initials: CA
authors.lastname: White
authors.forename: Ayub
authors.initials: A
authors.lastname: Akbari
authors.forename: Steve
authors.initials: S
authors.lastname: Doucette
authors.forename: Dean
authors.initials: D
authors.lastname: Fergusson
authors.forename: Tim
authors.initials: T
authors.lastname: Ramsay
authors.forename: Naser
authors.initials: N
authors.lastname: Hussain
authors.forename: Laurent
authors.initials: L
authors.lastname: Dinh
authors.forename: Guido
authors.initials: G
authors.lastname: Filler
authors.forename: Nathalie
authors.initials: N
authors.lastname: Lepage
authors.forename: Greg A
authors.initials: GA
authors.lastname: Knoll
mesh_terms: D000328:Adult; D000368:Aged; D003404:Creatinine / Q000097:blood*; D003430:Cross-Sectional Studies; D055316:Cystatin C / Q000097:blood*; D005260:Female; D006801:Humans; D007165:Immunosuppression Therapy; D019746:Intramolecular Oxidoreductases / Q000097:blood*; D016030:Kidney Transplantation; D054834:Lipocalins / Q000097:blood*; D008297:Male; D008875:Middle Aged; D055815:Young Adult
chemical_list: D055316:Cystatin C; D054834:Lipocalins; D003404:Creatinine; D019746:Intramolecular Oxidoreductases; C022466:prostaglandin R2 D-isomerase