ACP issues guidance statement on optimal HbA1c for patients with type 2 diabetes

March 17, 2008

The American College of Physicians Clinical Efficacy Assessment Subcommittee issued a statement regarding the optimal HbA1c target for people with type 2 diabetes.

The guidance statement is derived from a comprehensive and systematic review of other organizations' guidelines and is based on the strengths and weaknesses of these available recommendations. Guidelines from various organizations differed in whether they recommended a specific HgA1c target-and if they did, the target level differed. Most guidelines used an HgA1c target level of approximately 7%, but several recommended tailoring the level based on patient-specific factors.

On the basis of the review of available guidelines, the CEAS recommends that "to prevent microvascular complications of diabetes, the goal for glycemic control should be as low as is feasible without undue risk for adverse events or an unacceptable burden on patients. Treatment goals should be based on a discussion of the benefits and harms of specific levels of glycemic control with the patient. A hemoglobin A1c level less than 7% based on individualized assessment is a reasonable goal for many but not all patients."

The CEAS also recommends that the goal for hemoglobin A1c level should be based on individualized assessment of risk for complications from diabetes, comorbidity, life expectancy, and patient preferences. "For most people with Type 2 diabetes, the target HgA1c should be as close as possible to the normal without causing adverse events. While tighter control may be ideal for some patients, exceptions exist, particularly for patients with a high fall risk, a short life expectancy from comorbid conditions, or for patients of advanced age," stated Morello.

"For some patients making the correlation between HgA1c and their glucose meter reading might be confusing," continued Morello. In the near future, average blood glucose levels-rather than HgA1c-might be used to assess long-term glycemic control. "I feel we should use whatever target goal is most user friendly and understandable to the patient. Using an average plasma glucose concentration would certainly meet this purpose since conceptually it relates more with the glucose values patients see on their glucose meters," added Morello.

David M. Nathan, M.D., professor at Harvard University Medical School in Boston and chief of the diabetes unit medical service and the diabetes center at Massachusetts General Hospital, is the lead investigator of the A1c-Derived Average Glucose Examination (ADAGE) study. The objective of the study was to establish a validated relationship between HgA1c and average blood glucose across diabetes types, a wide range of HbA1c levels and age, and different ethnicities. "With a confirmed mathematical relationship hemoglobin A1c could be reported as an estimated average glucose. The advantage of reporting HbA1c into an estimated average glucose would be using the same units as the patients' self-monitoring of daily glycemia," stated Judith Kuenen, M.D., at the 43rd Annual Meeting of the European Association for the Study of Diabetes, held last September.

"No matter what measurement we use, the bottom line is that we want to help our patients better understand their diabetes and the effects that food, exercise, and medications have on their glucose concentrations and their overall long-term health," concluded Morello.

THE AUTHOR is a writer based in New Jersey.