How Tight is Right? Debating Issues of Optimal Glycemic Control

Supported by an unrestricted educational grant from AstraZeneca
Saturday, June 11, 2005
5:30-7:45 AM

Chair:
Willa Hsueh, MD

Faculty:
Steven M. Haffner, MD
David M. Nathan, MD

Reported by Kimberly McFarland, PhD

Dr Nathan began by pointing out that current A1C goals are arbitrary, even though they are based on the available clinical evidence. Because the DCCT demonstrated improvement in complications at the achieved A1C of 7, that was selected as a goal. However, the A1C goal in the trial was actually 6.05, lower than achieved. Furthermore, there was no breakpoint in complication improvement in the achieved glycemic range, and the current goals are actually higher than the normal physiologic range. In fact, the Framingham Offspring study demonstrated increased cardiovascular disease risk (CVD) risk with increasing A1C among normoglycemic individuals. Barriers to tighter glycemic control include hypoglycemia, nonphysiologic delivery, patient resistance, and physician resistance. While hypoglycemia did increase in the DCCT intensive control group, it is much rarer among type 2 diabetes patients. Other obstacles can be overcome with new delivery technologies and insulins, by presenting evidence of efficacy to patients, and through physician discussion of the issues. Dr Nathan concluded by indicating that setting a lower goal is necessary to achieving the most beneficial glycemic level. Dr Haffner focused on the role of insulin resistance in CVD risk. Current trials with insulin sensitizers may provide more evidence in this regard. He indicated that the weight gain associated with insulin initiation might contribute to insulin resistance and increased CVD risk in new diabetes patients and individuals with impaired glucose tolerance (IGT). He also stated that blood pressure (BP) control is also essential, a point on which the faculty agreed. The faculty seemed to agree that a broad, age-based policy on glucose control is needed, and that data from ongoing clinical trials will provide more information regarding the benefits of tight glycemic control and the role of insulin resistance in diabetes complications.