Effects of Rosiglitazone, Glyburide, and Metformin on β-Cell Function and Insulin Sensitivity in ADOPT

OBJECTIVE: ADOPT (A Diabetes Outcome Progression Trial) demonstrated that initial monotherapy with rosiglitazone provided superior durability of glycemic control compared with metformin and glyburide in patients with recently diagnosed type 2 diabetes. Herein, we examine measures of β-cell function and insulin sensitivity from an oral glucose tolerance test (OGTT) over a 4-year period among the three treatments. RESEARCH DESIGN AND METHODS: Recently diagnosed, drug-naïve patients with type 2 diabetes (4,360 total) were treated for a median of 4.0 years with rosiglitazone, metformin, or glyburide and were examined with periodic metabolic testing using an OGTT. RESULTS: Measures of β-cell function and insulin sensitivity from an OGTT showed more favorable changes over time with rosiglitazone versus metformin or glyburide. Persistent improvements were seen in those who completed 4 years of monotherapy and marked deterioration of β-cell function in those who failed to maintain adequate glucose control with initial monotherapy. CONCLUSIONS: The favorable combined changes in β-cell function and insulin sensitivity over time with rosiglitazone appear to be responsible for its superior glycemic durability over metformin and glyburide as initial monotherapy in type 2 diabetes.