The Risk of Heart Failure in Patients with Type 2 Diabetes Treated with Oral Agent Monotherapy

AIM: To determine if the risk of developing heart failure (HF) is associated with the use of sulfonylurea or metformin in patients with diabetes. METHODS: Retrospective cohort study of all adults without HF newly treated with oral antidiabetic drugs in Saskatchewan, Canada between 1991 and 1999. RESULTS: Of 5,631 diabetic subjects (mean age 66+/-13 years) newly treated with a single oral agent and followed for 4.7 (+/-2.2) years, 981 developed HF (4.1 cases per 100 patient years). The incidence of HF was greater in patients using sulfonylurea monotherapy (4.4 cases per 100 treatment years) than those taking metformin monotherapy (3.3 cases per 100 years), and users of high-dose sulfonylureas were more likely to develop incident HF than users of high-dose metformin (adjusted HR 1.24, 95% CI 1.01-1.54). Users of high-dose sulfonylureas were also more likely to develop HF (HR 1.38, 95% CI 1.20-1.60) than users of low-dose sulfonylureas; no such association existed for metformin users (HR 1.06, 95% CI 0.81-1.41). CONCLUSIONS: Users of higher doses of sulfonylurea exhibited a greater risk of developing HF. Clinicians should carefully weigh the need for high-dose sulfonylurea therapy in diabetic subjects with, or at high risk of, HF.