More evidence is emerging that prescribing sulphonylureas to patients with diabetes increases their cardiovascular risk when compared to metformin.
New research shows patients who were initiated with sulphonylurea had a significantly higher incidence of cardiovascular events compared to those initiated with Metformin after two years of follow-up.
It comes after UK research published in the European Heart Journal in April found monotherapy for type 2 diabetes patients with glimepiride, glibenclamide, glipizide or tolbutamide had between a 19% and 32% higher risk of all-cause and cardiovascular death compared with metformin. In patients with a history of heart attacks, this risk was 30%-53% higher.
The latest retrospective cohort study, presented at the American Diabetes Association conference in San Diego this week, analysed data from a cohort of patients aged 65 years old and above with type 2 diabetes who received their first prescription of sulphonylurea or metformin monotherapy between 2003 and 2007 and remained on it for at least 90 days from a medical record database.
Patients also had to have no prescriptions for diabetes drugs or previous cardiovascular events within the prior year and at least two years of follow-up after their first prescription.
Overall, 8,502 patients were included. After controlling for differences in baseline characteristics, patients who initiated with sulphonylurea had a significantly higher incidence of CVD events, at 12.4%, compared with those initiated with metformin after two years of follow-up.
The difference, researchers found, was mainly driven by the increased incidence of ischaemic heart disease, seen in 7.2% of patients with sulphonylurea, compared with 5.5% of patients with metformin.
The likelihood of having a cardiovascular event was 23% higher in patients initiated with sulphonyulrea than with metformin, and sulphonylurea use was associated with a shorter time to first cardiovascular event compared to metformin.
Dr Samuel Engel, associate clinical professor of medicine at the Albert Einstein College of Medicine in New York, concluded: ‘In a cohort of older patients with type 2 diabetes initiating antihyperglycemic therapy, the likelihood of experiencing a cardiovascular event was higher and these events occurred sooner in patients who started with sulphonylurea monotherapy than those who started with metformin.’