Almost 60% of patients with type 2 diabetes and moderate to severe renal impairment have been prescribed drugs at odds with expert guidelines, an Australian general practice study shows.

Drawing on the NPS MedicineInsight database, researchers from the University of Melbourne reviewed the records of 3500 patients who recorded at least two eGFR results of <60mL/min/1.73m2 and were prescribed a non-insulin diabetes medication over a 30-month period.

They found 58% of those prescribed metformin should have not been on the drug or on a lower dose, according to the advice in the Australian Diabetes Society’s 2014 guidelines.

This included 137 patients prescribed metformin despite having stage 4-5 chronic kidney disease, which, under the guidelines, is the cut-off point (see box, below).