Boning Up on Thiazolidinediones

The insulin sensitizer rosiglitazone (Avandia) improves glycemic control in patients with type 2 diabetes. However, the effect of this thiazolidinedione on cardiovascular outcomes is unclear. In a manufacturer-sponsored trial, investigators randomized 4447 patients (age range, 40–75; BMI >25 kg/m²; 48% women) who were receiving monotherapy with metformin or sulfonylurea to add rosiglitazone or to receive metformin plus sulfonylurea (active-control group).

At a mean follow-up of 5.5 years, occurrence of the primary endpoint (cardiovascular hospitalization or death) did not differ between the rosiglitazone (321 patients) and control groups (323 patients). However, risk for fatal and nonfatal heart failure was substantially higher among rosigli…