title: The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation is less accurate in patients with Type 2 diabetes when compared with healthy individuals.
abstract: OBJECTIVE
  To analyse the performances of Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and of Modification of Diet in Renal Disease (MDRD) study equations to estimate glomerular filtration rate (GFR) in patients with Type 2 diabetes mellitus with GFRs >60 ml/min and in healthy volunteers.
  
  
  METHODS
  This cross-sectional study included 111 individuals (56 patients with Type 2 diabetes and 55 healthy volunteers), aged 58 ± 9 years; 54 individuals were men (49%) and ninety-eight (88%) were white. Glomerular filtration rate was measured by the (51) Cr-EDTA single-injection method ((51) Cr-GFR) and estimated according to the standardized MDRD and CKD-EPI equations. Serum creatinine was measured by a traceable Jaffe method. Bland-Altman analysis was used to examine the agreement between measured and estimated GFR. Bias, accuracy and precision were evaluated.
  
  
  RESULTS
  In diabetic individuals, (51) Cr-GFR was 106 ± 27 ml/min/1.73 m(2) , CKD-EPI-estimated GFR 82 ± 18 ml/min/1.73 m(2) and MDRD-estimated GFR 80 ± 21 ml/min/1.73 m(2) (P < 0.001). In healthy volunteers, the corresponding values were 98 ± 20, 89 ± 13 and 84 ± 14 ml/min/1.73 m(2) (P < 0.001). The accuracy of CKD-EPI (P30) was higher in healthy volunteers than in diabetic patients (90 vs. 66%, respectively, P < 0.001). The MDRD equation performed as poorly as the CKD-EPI equation in individuals with Type 2 diabetes.
  
  
  CONCLUSIONS
  The CKD-EPI equation is less accurate in patients with Type 2 diabetes when compared with healthy individuals, with a 2.5-fold greater bias.
authors.affiliation: Endocrine Division Nephrology Division, Hospital de Clínicas de Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil. sandrasilveiro@terra.com.br
authors.forename: E G
authors.initials: EG
authors.lastname: Camargo
authors.forename: A A
authors.initials: AA
authors.lastname: Soares
authors.forename: A B
authors.initials: AB
authors.lastname: Detanico
authors.forename: L S
authors.initials: LS
authors.lastname: Weinert
authors.forename: F V
authors.initials: FV
authors.lastname: Veronese
authors.forename: E C
authors.initials: EC
authors.lastname: Gomes
authors.forename: S P
authors.initials: SP
authors.lastname: Silveiro
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D003404:Creatinine / Q000097:blood; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology* / Q000503:physiopathology; D003928:Diabetic Nephropathies / Q000453:epidemiology* / Q000503:physiopathology; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007674:Kidney Diseases / Q000453:epidemiology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged
chemical_list: D003404:Creatinine