title: Time to change the glomerular filtration rate estimating formula in primary care?
abstract: BACKGROUND
  The most commonly used equation for estimated glomerular filtration rate (eGFR) is nowadays the four-variable Modification of Diet in Renal Disease (MDRD) equation. This formula was derived from patients with non-diabetic chronic kidney disease (CKD) with mean GFR 40 ml/min.
  
  
  METHODS
  We compared the MDRD study equation and the recently developed Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation by applying the two formulas in 1747 middle-aged cardiovascular risk persons in primary care.
  
  
  RESULTS
  The prevalence of renal insufficiency defined as eGFR<60 ml/min was 6.7% (95% CI 5.6-8.0) according to the MDRD formula, and 3.6% (95% CI 2.8-4.6) according to the CKD-EPI formula. The subjects who were classified as having CKD according to the MDRD equation, but no-CKD according to the CKD-EPI formula, were mostly women (86%) and slightly younger than the subjects having CKD according to both formulas.
  
  
  CONCLUSIONS
  The characteristics of the subjects commonly treated in primary care resemble more closely the population from which the CKD-EPI than the MDRD study equation was derived from. Thus, we suppose that in general practice, the CKD-EPI equation is more suitable for estimating renal function than the MDRD equation.
authors.affiliation: Central Satakunta Health Federation of Municipalities, Harjavalta, Finland. paivi.e.korhonen@fimnet.fi
authors.forename: Päivi E
authors.initials: PE
authors.lastname: Korhonen
authors.forename: Hannu
authors.initials: H
authors.lastname: Kautiainen
authors.forename: Salme
authors.initials: S
authors.lastname: Järvenpää
authors.forename: Sirkka-Liisa
authors.initials: SL
authors.lastname: Kivelä
mesh_terms: D000368:Aged; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007677:Kidney Function Tests / Q000592:standards; D008297:Male; D008875:Middle Aged; D011320:Primary Health Care; D051436:Renal Insufficiency, Chronic / Q000175:diagnosis* / Q000503:physiopathology; D015203:Reproducibility of Results; D018570:Risk Assessment; D012737:Sex Factors