Troglitazone or metformin in combination with sulfonylureas for patients with type 2 diabetes?

BACKGROUND. Combination oral therapy is often used to control the hyperglyc emia of patients with type 2 diabetes. We compared the effectiveness of met formin and troglitazone when added to sulfonylurea therapy for patients wit h type 2 diabetes who had suboptimal blood glucose control. METHODS. We used a randomized 2-group design to compare the efficacy, safet y, and tolerability of troglitazone and metformin for patients with type 2 diabetes mellitus that was inadequately controlled with diet and oral sulfo nylureas. Thirty-two subjects were randomized to receive either troglitazon e or metformin for 14 weeks, including a 2-week drug-titration period. The primary outcome Variable was mean change in the level of glycosylated hemog lobin (Hb A(1c) ) from baseline. Secondary outcomes included mean changes f rom baseline in fasting plasma glucose and C-peptide levels, renal or metab olic side effects, and symptomatic tolerability. RESULTS. The addition of either troglitazone or metformin to oral sulfonylu rea therapy significantly decreased Hb A(1c) levels. Both treatment regimen s also significantly reduced fasting plasma glucose and C-peptide levels. W e found no significant differences between the treatment arms in efficacy, metabolic side effects, or tolerability. CONCLUSIONS. Our results demonstrate that troglitazone and metformin each s ignificantly improved Hb Al,, fasting plasma glucose, and C-peptide levels when added to oral sulfonylurea therapy for patients with type 2 diabetes w ho had inadequate glucose control.