Introduction: The optimal therapies for patients with diabetes mellitus (DM) and heart failure (HF) are unclear. We evaluated the comparative effectiveness of sulfonylurea versus biguanide (metformin) containing drugs, the two most commonly used classes of anti-hyperglycemic medications, in patients with DM and HF.
Methods: Using data from the Duke University Health System (DUHS) electronic health records, patients with both DM and HF were identified using billing codes. The inclusion date in the study cohort was the first date when a patient had both diagnoses in the medical record. Patients were identified as taking metformin or sulfonylurea drugs based on electronic prescriptions from the medical record. Follow-up was obtained using data from the electronic health record. Cox proportional hazards model were used to assess the relationship between sulfonylurea versus metformin for the outcome of (1) hospitalization for HF (HHF) and (2) all-cause mortality.
Results: Among patients with DM and HF (n= 9,418), 1,226 (13%) were prescribed sulfonylurea, 1,530 (16%) were prescribed metformin, and 486 (5%) were prescribed both drugs. The median age was 71.1 years for sulfonylurea users and 66.2 years for metformin users. After multivariable adjustment, sulfonylurea use was not associated with an increased risk of HHF (hazard ratio [HR] 0.99, 95% CI 0.83-1.08); however, sulfonylurea use was associated with a 15% increased risk of all-cause mortality (25.4% for sulfonylurea vs. 15.8 % for metformin users; HR 1.15, 95% confidence interval [CI] 1.09-1.76).
Conclusion: Among patients with DM and HF, sulfonylurea use at baseline, compared to metformin, was not associated with an increase risk of HHF; however, sulfonylurea use was associated with an increased risk of all-cause mortality. Prospective randomized trials of sulfonylurea versus metformin in patients with DM and HF are warranted.