title: Estimating glomerular filtration rate: Performance of the CKD-EPI equation over time in patients with type 2 diabetes.
abstract: OBJECTIVE
  To assess the performance of the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation at baseline and longitudinally in people with type 2 diabetes.
  
  
  METHODS
  Adults with type 2 diabetes attending Austin Health, Melbourne, with≥3 prospective GFR measurements were included in this retrospective study. Plasma disappearance rate of DTPA (diethylene-triamine-penta-acetic acid) was used to calculate measured GFR (mGFR) and compared to estimated GFR (eGFR). The agreement between mGFR and eGFR was estimated using Intraclass Correlation Coefficient (ICC).
  
  
  RESULTS
  152 patients had a median of 4 (IQR: 3, 5) mGFR measurements over a period of 11years (IQR: 9, 12). The difference between mGFR and eGFR increased proportionally to the magnitude of the GFR, increasing by 0.2ml/min/1.73m(2) for every 1ml/min/1.73m(2) increase in mGFR, indicative of proportional bias. At lower mGFR levels, eGFR overestimated mGFR, and at higher mGFR levels, eGFR underestimated mGFR. There was a significant association between LDL cholesterol, triglycerides, HbA1c, diastolic blood pressure and the difference between mGFR and eGFR.
  
  
  CONCLUSIONS
  The CKD-EPI formula underestimates mGFR and the rate of decline of mGFR in patients with type 2 diabetes with an mGFR greater than 60ml/min/1.73m(2). The association between LDL cholesterol, triglycerides, HbA1c, diastolic blood pressure and the difference between mGFR and eGFR warrants further study.
authors.affiliation: Austin Health Endocrine Centre, Heidelberg, VIC, Australia.
authors.forename: Anna J
authors.initials: AJ
authors.lastname: Wood
authors.affiliation: Florey Institute of Neuroscience and Mental Health, Heidelberg, VIC, Australia; RMIT University, Melbourne, VIC, Australia.
authors.forename: Leonid
authors.initials: L
authors.lastname: Churilov
authors.affiliation: Austin Health Endocrine Centre, Heidelberg, VIC, Australia.
authors.forename: Nayomi
authors.initials: N
authors.lastname: Perera
authors.affiliation: Austin Health Nuclear Medicine Department, Heidelberg, VIC, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Thomas
authors.affiliation: Austin Health Nuclear Medicine Department, Heidelberg, VIC, Australia.
authors.forename: Aurora
authors.initials: A
authors.lastname: Poon
authors.affiliation: Department of Medicine Austin Health, The University of Melbourne, Melbourne, VIC, Australia; Department of Endocrinology and Diabetes, St Vincent's Hospital, The University of Melbourne, Melbourne, VIC, Australia.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: MacIsaac
authors.affiliation: Austin Health Endocrine Centre, Heidelberg, VIC, Australia; Department of Medicine Austin Health, The University of Melbourne, Melbourne, VIC, Australia.
authors.forename: George
authors.initials: G
authors.lastname: Jerums
authors.affiliation: Austin Health Endocrine Centre, Heidelberg, VIC, Australia; Department of Medicine Austin Health, The University of Melbourne, Melbourne, VIC, Australia; Menzies School of Health Research, Darwin, NT, Australia. Electronic address: elif.ekinci@unimelb.edu.au.
authors.forename: Elif I
authors.initials: EI
authors.lastname: Ekinci
mesh_terms: D000465:Algorithms; D003924:Diabetes Mellitus, Type 2 / Q000150:complications*; D003928:Diabetic Nephropathies / Q000097:blood / Q000175:diagnosis* / Q000503:physiopathology; D018450:Disease Progression; D005260:Female; D005919:Glomerular Filtration Rate; D006786:Hospitals, Urban; D006801:Humans; D007275:Injections, Intravenous; D007668:Kidney / Q000503:physiopathology*; D008137:Longitudinal Studies; D008297:Male; D010044:Outpatient Clinics, Hospital; D019275:Radiopharmaceuticals / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics; D065667:Renal Elimination; D051436:Renal Insufficiency, Chronic / Q000097:blood / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D012189:Retrospective Studies; D012720:Severity of Illness Index; D012727:Sex Characteristics; D016284:Technetium Tc 99m Pentetate / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics; D062606:Tertiary Care Centers; D014739:Victoria
chemical_list: D019275:Radiopharmaceuticals; D016284:Technetium Tc 99m Pentetate
keywords: CKD-EPI; Estimated GFR; Measured GFR; Renal function; Type 2 diabetes