CHICAGO—Australian Aboriginal patients with type 2 diabetes have adramatically increased risk of chronic kidney disease (CKD) compared with Anglo-Celt patients from the same urban community, according to data released at the 73rd Scientific Sessions of the American Diabetes Association.

Timothy M. E. Davis, MD, Head of Fremantle Unit, School of Medicine and Pharmacology at the University of Western Australia, and associates conducted a study to compare the characteristics of nephropathy complicating type 2 diabetes in indigenous Australians with those of the majority Anglo-Celt (AC) ethnicity from the same geographical area.

Renal disease is recognized as a chronic complication of diabetes that is increased substantially in Australian Aboriginal patients with type 2 diabetes.  For example, Aboriginal type 2 diabetics have been found to have an incidence of end-stage renal disease that is 20 to 30 times that in Caucasian type 2 patients. High rates of albuminuria have also been documented in this population; in one study, 50% of all diabetic individuals had albuminuria regardless of age.

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Some investigators have suggested that urban-dwelling indigenous patients are less susceptible to nephropathy than those residing in remote areas, he added. However, there have been no comprehensive comparisons of the prevalence and predictors of nephropathy between racial groups in a multi-cultural setting in Australia.

The present analysis included 105 Aboriginal type 2 diabetes patients and 827 AC individuals living in the same area who were drawn from the ongoing community-based Fremantle Diabetes Study (FDS). The FDS is an observational study of diabetes in people living in the primary catchment area of Fremantle Hospital.  

Participants had complete baseline data including serum creatinine (from which estimated glomerular filtration rate (eGFR) was calculated using the CKD Epidemiology Collaboration equation) and urinary albumin:creatinine.

Results showed that the percentage of Aboriginal patients with an eGFR below 60 mL/min/1.73m2 was similar to that in the AC group (26.9% and 32.2%).  However, Aboriginal patients were more likely to have micro- and macroalbuminuria (36.6% and 25.8% vs. 34.5 and 5.4 %, respectively).

In addition, 19.6% of Aboriginal patients were at very high risk based on the Kidney Disease Improving Global Outcomes prognostic CKD categories compared with 10% of the AC cohort. A “very high risk” classification referred to an eGFR 30-59 and at least microalbuminuria, an eGFR below 30, or need for renal replacement therapy.

After controlling for potential confounders including age and diabetes duration, the investigators found that Aboriginal patients were nearly seven times as likely as Anglo-Celt patients to fall into the very high risk CKD category. “This finding suggests that urban-dwelling Aboriginal patients with type 2 diabetes have the same marked propensity for nephropathy as their counterparts from remote or rural settings,” Dr. Davis observed.

The substantially increased risk of CKD in type 2 Aboriginal Australians may reflect an increased susceptibility to microvascular complications including nephropathy, retinopathy, and neuropathy, Dr. Davis said.