Letters Section Editor: Robert M. Golub, MD, Senior Editor.
In Reply: Drs Giugliano and Esposito raise a question regarding the importance of changes in glucose control in the CHICAGO trial. With respect to the absolute changes in HbA1c levels in response to the randomized drug therapy, a large percentage of participants was using sulfonylurea monotherapy or sulfonylurea-metformin combination therapy at baseline. Because randomization was to glimepiride or pioglitazone, it was necessary for these patients to discontinue baseline sulfonylurea therapy before randomization. The replacement of one sulfonylurea with another, or with pioglitazone, led to the observed changes in HbA1c levels over the course of the study. The gradual increase in HbA1c levels in patients randomized to glimepiride is consistent with observations regarding the natural history of β-cell function in type 2 diabetes and with a potential role for thiazolidinediones in better preservation of glucose control over time.1,2
Mazzone T. Pioglitazone vs Glimepiride and Carotid Intima-Media Thickness—Reply. JAMA. 2007;297(12):1315-1317. doi:10.1001/jama.297.12.1316-b