title: Hyperfiltration in Indigenous Australians with and without diabetes.
abstract: BACKGROUND
  Hyperfiltration (HF) has been linked to the development of diabetic kidney disease (DKD), but the causative or predictive role of HF in the pathogenesis of DKD still remains unclear. To date, there have been no studies of HF in Indigenous Australians, a population with high rates of both diabetes and end-stage kidney disease. We aimed to compare the characteristics and frequency of HF in Indigenous Australians with and without type 2 diabetes.
  
  
  METHODS
  Indigenous Australian participants, recruited across five pre-defined strata of health, diabetes status and kidney function, had a reference glomerular filtration rate (GFR) measured using plasma disappearance of iohexol [measured GFR(mGFR)] over 4 h. HF was defined in various ways: (i) mGFR > 144 mL/min/1.73 m(2), which is mGFR > 1.96 × SD above the mean of the mGFR in non-diabetic participants with normal albuminuria and normal renal function (mGFR > 90 mL/min/1.73 m(2)); (ii) age-corrected mGFR (>144 mL/min/1.73 m(2)) to account for the effect of ageing on GFR in subjects over 40 years of age with cut-off 1 mL/min/1.73 m(2) lower for every year; (iii) mGFR > 144 mL/min, without correction for body surface area or age, as well as (iv) mGFR > 125 mL/min/1.73 m(2), without adjustment for age.
  
  
  RESULTS
  A total of 383 Indigenous participants, 125 with and 258 without diabetes, with mGFR > 90 mL/min/1.73 m(2) were studied. The proportion of participants with HF was 7% using mGFR > 144 mL/min/1.73 m(2), 11% using the age-adjusted definition, 19% using mGFR > 144 mL/min and 27% using mGFR > 125 mL/min/1.73 m(2). Diabetes was more common in participants with HF (40-74%) compared with normofiltering participants (28-31%), regardless of the definition of HF.
  
  
  CONCLUSIONS
  HF exists in Indigenous Australians with and without diabetes. A greater proportion of participants had diabetes in HF group compared with normofiltration group. Long-term follow-up of this cohort is necessary to determine if HF plays a role in the development of DKD and non-DKD.
authors.affiliation: Menzies School of Health Research, Charles Darwin University, Darwin, Australia Department of Medicine, Austin Health and the University of Melbourne, Melbourne, Australia.
authors.forename: Elif I
authors.initials: EI
authors.lastname: Ekinci
authors.affiliation: Menzies School of Health Research, Charles Darwin University, Darwin, Australia.
authors.forename: Jaquelyne T
authors.initials: JT
authors.lastname: Hughes
authors.affiliation: Menzies School of Health Research, Charles Darwin University, Darwin, Australia.
authors.forename: Mark D
authors.initials: MD
authors.lastname: Chatfield
authors.affiliation: Menzies School of Health Research, Charles Darwin University, Darwin, Australia.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Lawton
authors.affiliation: SydPath, St Vincent's Hospital, Sydney, Australia.
authors.forename: Graham R D
authors.initials: GR
authors.lastname: Jones
authors.affiliation: Department of Medicine, Austin Health and the University of Melbourne, Melbourne, Australia.
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Ellis
authors.affiliation: Menzies School of Health Research, Charles Darwin University, Darwin, Australia.
authors.forename: Alan
authors.initials: A
authors.lastname: Cass
authors.affiliation: Royal Perth Hospital, Perth, Australia.
authors.forename: Mark
authors.initials: M
authors.lastname: Thomas
authors.affiliation: Department of Endocrinology and Diabetes, St Vincent's Hospital Melbourne and the University of Melbourne, Melbourne, Australia.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: MacIsaac
authors.affiliation: School of Population Health, University of South Australia, Adelaide, Australia.
authors.forename: Kerin
authors.initials: K
authors.lastname: O'Dea
authors.affiliation: Department of Medicine, Austin Health and the University of Melbourne, Melbourne, Australia.
authors.forename: George
authors.initials: G
authors.lastname: Jerums
authors.affiliation: Menzies School of Health Research, Charles Darwin University, Darwin, Australia.
authors.forename: Louise J
authors.initials: LJ
authors.lastname: Maple-Brown
mesh_terms: D000328:Adult; D000419:Albuminuria / Q000175:diagnosis* / Q000209:etiology; D001315:Australia / Q000453:epidemiology; D001830:Body Surface Area; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000208:ethnology / Q000503:physiopathology*; D003928:Diabetic Nephropathies / Q000208:ethnology / Q000209:etiology / Q000503:physiopathology*; D005260:Female; D005919:Glomerular Filtration Rate; D006303:Health Services, Indigenous; D006801:Humans; D008297:Male; D008875:Middle Aged; D051436:Renal Insufficiency, Chronic / Q000175:diagnosis* / Q000209:etiology
keywords: CKD-EPI equation; diabetic kidney disease; ethnicity; glomerular filtration rate; hyperfiltration