Comparative effectiveness of sulfonylurea and metformin monotherapy on cardiovascular events in type 2 diabetes mellitus: a cohort study.

BACKGROUND

The effects of sulfonylureas and metformin on outcomes of cardiovascular disease (CVD) in type 2 diabetes are not well-characterized.

OBJECTIVE

To compare the effects of sulfonylureas and metformin on CVD outcomes (acute myocardial infarction and stroke) or death.

DESIGN

Retrospective cohort study.

SETTING

National Veterans Health Administration databases linked to Medicare files.

PATIENTS: Veterans who initiated metformin or sulfonylurea therapy for diabetes. Patients with chronic kidney disease or serious medical illness were excluded.

MEASUREMENTS: Composite outcome of hospitalization for acute myocardial infarction or stroke, or death, adjusted for baseline demographic characteristics; medications; cholesterol, hemoglobin A1c, and serum creatinine levels; blood pressure; body mass index; health care utilization; and comorbid conditions.

RESULTS

Among 253 690 patients initiating treatment (98 665 with sulfonylurea therapy and 155 025 with metformin therapy), crude rates of the composite outcome were 18.2 per 1000 person-years in sulfonylurea users and 10.4 per 1000 person-years in metformin users (adjusted incidence rate difference, 2.2 [95% CI, 1.4 to 3.0] more CVD events with sulfonylureas per 1000 person-years; adjusted hazard ratio [aHR], 1.21 [CI, 1.13 to 1.30]). Results were consistent for both glyburide (aHR, 1.26 [CI, 1.16 to 1.37]) and glipizide (aHR, 1.15 [CI, 1.06 to 1.26]) in subgroups by CVD history, age, body mass index, and albuminuria; in a propensity score-matched cohort analysis; and in sensitivity analyses.

LIMITATION: Most of the veterans in the study population were white men; data on women and minority groups were limited but reflective of the Veterans Health Administration population.

CONCLUSION

Use of sulfonylureas compared with metformin for initial treatment of diabetes was associated with an increased hazard of CVD events or death.

PRIMARY FUNDING SOURCE: Agency for Healthcare Research and Quality and the U.S. Department of Health and Human Services.