The burden of chronic kidney disease in Australian patients with type 2 diabetes (the NEFRON study)

Objective: To estimate the frequency of chronic kidney disease (CKD) in a clinic-based sample of patients with type 2 diabetes in the setting of Australian primary care. Design, setting and participants: Expressions of interest were invited from all registered general practitioners in Australia: 500 GP investigators were randomly selected from each stratum (state and urban versus rural location), proportional to the census population, and asked to recruit and provide data for 10-15 consecutively presenting adults with type 2 diabetes between April and September 2005. Main outcome measures: Estimated glomerular filtration rate (eGFR) less than 60 mL/min/1.73 m(2) and evidence of kidney damage on urinalysis (eg, microalbuminuria). Results: 348 GP investigators submitted data for 3893 individuals with type 2 diabetes (52% men; median age, 66 years). Almost one in every four patients consulting their GPs had an eGFR < 60 mL/min/1.73 m(2) (23.1%; 95% Cl, 21.8%-24.5%). More than one in three had an elevated urinary albumin-creatinine ratio (ACR) (34.6%; 95% Cl, 33.3%-35.9%). There was an overlap of 10.4% of patients with both an eGFR < 60 mL/min/1.73 m(2) and an elevated urinary ACR, meaning that almost one in two patients with type 2 diabetes consulting their GPs (47.1%; 95% Cl, 45.8%-48.4%) had CKD. CKD was significantly more common in women, in older people, and in individuals with established macrovascular disease. Conclusion: CKD is a common complication of type 2 diabetes, found in about half of all patients with type 2 diabetes consulting their GPs. Efforts to increase the recognition of CKD will lead to improved care, and possibly survival, of patients with type 2 diabetes.