The role of CKD in the prescription of anti-diabetic agents by Australian GPs (NEFRON-4)
Objectives: To describe the pattern of use of antidiabetic agents in a population-based sample of patients with type 2 diabetes in the Australian primary care setting and examine the influence of impaired kidney function, and its identification by GPs, on patterns of prescribing.
Design, setting and participants: Expressions of interest (EOI) were invited from all registered GPs across Australia. 500 GP investigators were randomly selected form EOIs, proportional to the census population. Investigators were requested to recruit 10-15 consecutively presenting adult patients with established type 2 diabetes, irrespective of reason for visit. Participants were assessed by history, physical examination and data from the most recent blood tests and urinalysis
Main outcome measures: The pattern of use of antidiabetic agents was compared with the estimated glomerular filtration rate (eGFR) and estimates of kidney function made by GPs themselves and their classification of kidney function on an individual patient basis.
Results: Metformin (63.4%), sulphonylureas (44.6%) and thiazolidinediones (6.7%) were the most commonly used agents. Contrary to national prescribing recommendations, over half of all individuals with moderate to severe renal impairment (53.1%) were prescribed metformin, with a drop-off seen only in patients with a serum creatinine >150µM (30.1%). The proportional usage of sulphonylureas with active metabolites was similar in patients with and without renal impairment (21.3 vs. 23.6%)- even where prescribers identified impairment of renal function.
Conclusion: Continuing support to improve awareness of low eGFR and its implications for the management of type 2 diabetes appears warranted in Australian primary care.