Doctors should not prescribe sulfonylureas as first-line treatment for type 2 diabetes because of a higher risk of mortality compared with metformin.

That is the key finding from data presented at the European Association for the Study of Diabetes meeting in Barcelona. Researchers, led by Craig Currie from Cardiff University, evaluated the comparative risk of all-cause mortality for patients exposed to first-line diabetes monotherapy with either mettformin for sulfonylureas such as glipizide, gliclazide or glibenclamide.

The latter class of treatments are commonly prescribed as first-line therapy in developed countries (e.g. 7% of people with type 2 diabetes in the UK). The researchers extracted data from the Clinical Practice Research Datalink, which has information on 10% of all patients treated in primary care in the UK. Patients with type 2 diabetes initiated with first-line, glucose-lowering treatments between 2000 and 2012 were selected.
The analysis showed that 76,811 patients were prescribed metformin monotherapy (with a mean follow-up of three years) and 15,687 sulfonylureas (also three year follow-up). Patients prescribed the latter were 58% more likely to die from any cause than those prescribed metformin.
Prof Currie said that not all doctors "are fully informed about the risks and benefits of commonly used drugs [and] failure to identify the higher mortality associated with certain drugs could also be regarded as a failure of the regulatory system". He concluded that "treatment with first-line monotherapy with sulfonylureas should be reconsidered".