title: The four-variable modification of diet in renal disease formula underestimates glomerular filtration rate in obese type 2 diabetic individuals with chronic kidney disease.
abstract: OBJECTIVE
  GFR is commonly estimated using the four-variable Modification of Diet in Renal Disease (MDRD) formula and this forms the basis for classification of chronic kidney disease (CKD). We investigated the effect of obesity on the estimation of glomerular filtration rate in type 2 diabetic participants with CKD.
  
  
  METHODS
  We enrolled 111 patients with type 2 diabetes mellitus in different stages of CKD. GFR was measured using (51)Cr-labelled EDTA plasma clearance and was estimated using the four-variable MDRD formula.
  
  
  RESULTS
  The bias between estimated and measured GFR was -22.4 (-33.8 to -11.0) p < 0.001 in the obese group compared with -6.04 (-17.6 to -5.5) p = 0.299 in the non-obese group. When GFR was indexed to body surface area of 1.73 m(2), the bias remained significant at -9.4 (-13.4 to -5.4) p < 0.001 in the obese participants.
  
  
  CONCLUSIONS
  This study suggests that the four-variable MDRD formula significantly underestimates GFR in obese type 2 diabetic participants with CKD.
authors.affiliation: Obesity & Endocrinology Research Unit, Clinical Sciences Centre, University Hospital Aintree, University of Liverpool, Longmoor Lane, Liverpool L9 7AL, UK.
authors.forename: S
authors.initials: S
authors.lastname: Nair
authors.forename: V
authors.initials: V
authors.lastname: Mishra
authors.forename: K
authors.initials: K
authors.lastname: Hayden
authors.forename: P J G
authors.initials: PJ
authors.lastname: Lisboa
authors.forename: B
authors.initials: B
authors.lastname: Pandya
authors.forename: S
authors.initials: S
authors.lastname: Vinjamuri
authors.forename: K J
authors.initials: KJ
authors.lastname: Hardy
authors.forename: J P H
authors.initials: JP
authors.lastname: Wilding
mesh_terms: D000368:Aged; D015992:Body Mass Index; D001830:Body Surface Area; D002908:Chronic Disease; D015897:Comorbidity; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology / Q000503:physiopathology*; D005247:Feeding Behavior; D005260:Female; D005526:Food, Formulated; D005919:Glomerular Filtration Rate / Q000502:physiology*; D006801:Humans; D007674:Kidney Diseases / Q000453:epidemiology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology / Q000503:physiopathology*