title: Estimating glomerular filtration rate in diabetes: a comparison of cystatin-C- and creatinine-based methods.
abstract: OBJECTIVE
  We compared the predictive performance of a GFR based on serum cystatin C levels with commonly used creatinine-based methods in subjects with diabetes.
  
  
  METHODS
  In a cross-sectional study of 251 consecutive clinic patients, the mean reference (plasma clearance of (99m)Tc-diethylene-triamine-penta-acetic acid) GFR (iGFR) was 88+/-2 ml min(-1) 1.73 m(-2). A regression equation describing the relationship between iGFR and 1/cystatin C levels was derived from a test population (n=125) to allow for the estimation of GFR by cystatin C (eGFR-cystatin C). The predictive performance of eGFR-cystatin C, the Modification of Diet in Renal Disease 4 variable formula (MDRD-4) and Cockcroft-Gault (C-G) formulas were then compared in a validation population (n=126).
  
  
  RESULTS
  There was no difference in renal function (ml min(-1) 1.73 m(-2)) as measured by iGFR (89.2+/-3.0), eGFR-cystatin C (86.8+/-2.5), MDRD-4 (87.0+/-2.8) or C-G (92.3+/-3.5). All three estimates of renal function had similar precision and accuracy.
  
  
  CONCLUSIONS
  Estimates of GFR based solely on serum cystatin C levels had the same predictive potential when compared with the MDRD-4 and C-G formulas.
authors.affiliation: Endocrine Centre and the Department of Medicine, Austin Health and University of Melbourne, Heidelberg Repatriation Hospital, Level 2, Centaur Building, Heidelberg West, VIC, 3081, Australia. r.macisaac@unimelb.edu.au
authors.forename: R J
authors.initials: RJ
authors.lastname: Macisaac
authors.forename: C
authors.initials: C
authors.lastname: Tsalamandris
authors.forename: M C
authors.initials: MC
authors.lastname: Thomas
authors.forename: E
authors.initials: E
authors.lastname: Premaratne
authors.forename: S
authors.initials: S
authors.lastname: Panagiotopoulos
authors.forename: T J
authors.initials: TJ
authors.lastname: Smith
authors.forename: A
authors.initials: A
authors.lastname: Poon
authors.forename: M A
authors.initials: MA
authors.lastname: Jenkins
authors.forename: S I
authors.initials: SI
authors.lastname: Ratnaike
authors.forename: D A
authors.initials: DA
authors.lastname: Power
authors.forename: G
authors.initials: G
authors.lastname: Jerums
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003404:Creatinine / Q000032:analysis*; D003430:Cross-Sectional Studies; D055316:Cystatin C; D015891:Cystatins / Q000032:analysis*; D005919:Glomerular Filtration Rate; D006801:Humans; D008875:Middle Aged; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity
chemical_list: C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins; D003404:Creatinine