Association of Hypoglycemic Treatment Regimens With Cardiovascular Outcomes in Overweight and Obese Subjects With Type 2 Diabetes: A substudy of the SCOUT trial

OBJECTIVE: To assess the association of hypoglycemic treatment regimens with cardiovascular adverse events and mortality in a large population of type 2 diabetic patients at increased cardiovascular risk. RESEARCH DESIGN AND METHODS: This analysis included 8,192 overweight patients with type 2 diabetes from the Sibutramine Cardiovascular Outcomes (SCOUT) trial randomized to lifestyle intervention with or without sibutramine for up to 6 years. Patients were grouped according to hypoglycemic treatment at baseline. The primary end point was the time from randomization to the first occurrence of a primary outcome event (POE), nonfatal myocardial infarction, nonfatal stroke, resuscitation after cardiac arrest, or cardiovascular death. Multivariable Cox proportional hazards regression models were used to assess the impact of antiglycemic treatment on POE and all-cause mortality. RESULTS: Treatments for type 2 diabetes were as follows: diet alone (n = 1,394 subjects), metformin monotherapy (n = 1,631), insulin monotherapy (n = 1,116), sulfonylurea monotherapy (n = 1,083), metformin plus sulfonylurea (n = 1,565), and metformin plus insulin (n = 1,000); 905 subjects experienced a POE and 708 died. Metformin monotherapy was associated with lower risk of POE than insulin (hazard ratio [HR], 0.74; 95% CI, 0.57–0.95; P = 0.02). Diet alone also was associated with lower risk of POE (HR, 0.65; 95% CI, 0.48–0.87; P = 0.004). Metformin monotherapy also was associated with lower mortality (HR, 0.73; 95% CI, 0.54–0.99; P < 0.05), whereas no other monotherapies or combination therapies were significantly associated with POE or all-cause mortality compared with insulin as monotherapy. CONCLUSIONS: In obese patients with type 2 diabetes and high risk of cardiovascular disease, monotherapy with metformin or diet-only treatment was associated with lower risk of cardiovascular events than treatment with insulin.