Chronic kidney disease in the Top End of the Northern Territory of Australia, 2002-2011: A retrospective cohort study using existing laboratory data

Background: The Northern Territory of Australia has a very high incidence of treated end-stage kidney disease (ESKD), largely confined to Indigenous Australians living in remote, under-resourced areas. Surveillance of chronic kidney disease (CKD) is still in its infancy in Australia. We estimate the prevalence and rate of progression of measured CKD across a region using inexpensive readily available laboratory information. 

Methods: Using a retrospective de-identified extraction of all records with a serum creatinine or urinary albumin-to-creatinine ratio from the single largest ambulatory pathology provider to the Top End of the Northern Territory of Australia between 1st February 2002 and 31st December 2011, the yearly total and age-specific prevalence of measured microalbuminuria, overt albuminuria and estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m², and the prevalence of progressive CKD, were calculated. 

Results: There was a steady increase in the proportion tested across all health districts in the region, more prominent in non-urban districts. In 2009, the regional adult prevalence of measured microalbuminuria and overt albuminuria was as high as 8.1 %, overt albuminuria alone up to 3.0 % and eGFR < 60 up to 2.3 %. Rates of progressive disease were extremely high, particularly for those with albuminuria (53.1-100 % for those with urinary albumin-creatinine ratio > 300 mg/mmol). 

Conclusions: The rates of testing, particularly in districts of high measured prevalence of markers of CKD, are encouraging. However, extremely high rates of progressive CKD are troubling. Further describing the outcomes of CKD in this population would require analysis of linked datasets.