Researchers: Dr Louise Maple-Brown (Menzies School of Health Research, Darwin), Dr Paul Lawton (Director, NT Renal Services), Prof Kerin O’Dea (Director, Sansom Institute, Uni SA), Prof Wendy Hoy (University of Queensland), Dr Alan Cass (The George Institute), Prof George Jerums (Austin Health, Melbourne), Dr Mark Thomas (Royal Perth Hospital), Dr Kevin Warr (Royal Perth Hospital), Dr Jaqui Hughes (Menzies School of Health Research), Dr Graham Jones (SydPath, St Vincents Hospital, Sydney)
Funding: NHMRC project grant 545202, 2009-2011
Project summary: There is an overwhelming burden of chronic kidney disease and end-stage renal failure in Indigenous Australians. It is vital that we are able to accurately measure kidney function in this high risk population. Glomerular filtration rate (GFR) is the best overall marker of kidney function. However, differences in body build and body composition between Indigenous and non-Indigenous Australians suggest that estimates of GFR derived for European populations may not be appropriate for Indigenous Australians. The burden of kidney disease is borne disproportionately by Indigenous Australians in central and northern Australia, with significant heterogeneity amongst these groups, thus differences in body build and body composition likely also affect the accuracy of GFR between different Indigenous groups.
By assessing kidney function in these high-risk Indigenous Australian populations from Northern Queensland, Northern Territory, and Western Australia, we aim to determine a validated and practical measure of GFR suitable for use in all Indigenous Australians. We will compare the accuracy of the following techniques to measure GFR to the reference GFR measured by the plasma disappearance rate of iohexol: Modification of Diet in Renal Disease 4 variable formula (MDRD-4), Cockcroft-Gault formula and cystatin C. Detailed assessment of body build and body composition will be performed using anthropometric measurements, skinfold thickneses and bioelectrical impedance and a sub-study in larger centres will use dual-energy absorptiometry (DXA). It is possible that these measures may enable a modification (derived from a simple measure of fat free mass in each participant) to be incorporated into the MDRD formula for estimating GFR. Alternatively, a biochemical measure of kidney function other than serum creatinine may be found to be the most reliable measure of kidney function in all Indigenous Australians. We do not believe that a single correction factor (similar to that for African Americans) is appropriate or practical for Indigenous Australians. Once eGFR methods are validated by this study it would lay the foundations for future interventional studies that aim to ameliorate the progression of kidney function to ESRF in Indigenous Australians.
Progress: Ongoing