title: [Assessment of the new CKD-EPI equation to estimate the glomerular filtration rate].
abstract: BACKGROUND
  A recent report by the CKD-EPI Chronic Kidney Disease Epidemiology Collaboration) group describes a new equation to estimate the glomerular filtration rate (GFR). This equation has been developed from a population of 8,254 subjects who had the GFR measured by iothalamate clearance (mean 68 mL/min/1.73 m2, SD 40 mL/min/1.73 m2). It includes variables such as serum creatinine, age, sex and race with different formula according to race, sex and creatinine value. The CKD-EPI equation improved the accuracy and precision results of the current first-choice MDRD-IDMS (Modification of Diet in Renal Disease-Isotopic Dilution Mass Spectrometry) formula, specially for GFR > 60 mL/min/1.73 m2 in a group of 3,896 subjects.
  
  
  METHODS
  The goal of our study was to compare the estimated GFR by using the new equation CKD-EPI with MDRD-IDMS in a wide cohort of 14,427 patients (5,234 women and 9,193 men), and to analyze the impact of the new CKD-EPI formula on the staging of patients with CKD.
  
  
  RESULTS
  Mean estimated GFR was 0.6 mL/min/1.73 m2 higher with CKD-EPI as compared to MDRD-IDMS for the whole group, 1.9 mL/min/1.73 m2 higher for women and 0.2 mL/min/1.73 m2 lower for men. The percentage of CKD staging concordancy between equations varied from 79.4 % for stage 3A and 98.6% for stage 5. For those patients younger than 70 years, 18.9 % and 24 % MDRD-IDMS stages 3B and 3A were reclassified as CKD 3A and 2 by CKD-EPI, respectively. For the same stages in the group younger than 70 years, the percentage of reclassified patients increased up to 34.4% and 33.4%, respectively.
  
  
  CONCLUSIONS
  The new CKD-EPI equation to estimate the GFR reclassifies an important number of patients to higher CKD stages (higher GFR), specially younger women, classified as CKD stage 3 by MDRD-IDMS.
authors.affiliation: Servicios de Laboratorio, Fundació Puigvert, Universitat Autònoma de Barcelona FP/UAB, Red Nacional de Investigación en Nefrología (REDINREN), Instituto de Investigación Carlos III, Madrid, Spain. rmontanes@fundacio-puigvert.es
authors.forename: R
authors.initials: R
authors.lastname: Montañés Bermúdez
authors.forename: J
authors.initials: J
authors.lastname: Bover Sanjuán
authors.forename: A
authors.initials: A
authors.lastname: Oliver Samper
authors.forename: J A
authors.initials: JA
authors.lastname: Ballarín Castán
authors.forename: S
authors.initials: S
authors.lastname: Gràcia García
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D002908:Chronic Disease; D015331:Cohort Studies; D003404:Creatinine / Q000097:blood; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007483:Iothalamic Acid / Q000493:pharmacokinetics; D007674:Kidney Diseases / Q000145:classification / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011507:Proteinuria / Q000209:etiology / Q000503:physiopathology; D012720:Severity of Illness Index; D012737:Sex Factors; D055815:Young Adult
chemical_list: D007483:Iothalamic Acid; D003404:Creatinine