Point: The Reporting of Estimated Glucose with Hemoglobin A1c

Abstract

Healthcare providers and patients with diabetes evaluate the efficacy of glycemic control by 2 strategies. One strategy involves self-monitoring of blood glucose (SMBG)1 by patients, with portable meters and continuous blood glucose monitors or sensing devices. Patients use these glucose values for daily decision-making to adjust medication doses and/or modify food intake or exercise regimens. Blood glucose fluctuates widely over minutes to hours, depending on food intake, exercise, insulin, and physical and emotional stressors. Values obtained by SMBG, therefore, do not signify average glucose (AG) concentrations. When an estimate of glucose values over time is desired, cumulative results can be downloaded from the patient’s meter in the provider’s office. These data are useful for determining whether current diabetes therapies are appropriate or need adjustment. Unfortunately, a number of barriers to blood glucose monitoring that may exist in clinical practice make it difficult to obtain an adequate amount of reliable data from patient logbooks. Barriers to SMBG implementation, as identified by patients with diabetes and their healthcare teams, include not only physical, financial, cognitive, and emotional factors, but also time constraints and inconvenience (1). In addition, patient follow-through may be lacking because of inadequate education or communication between patient and healthcare provider regarding what information is needed and why it is necessary. For this reason, it is important that hemoglobin A1c (Hb A1c) be measured regularly. The second strategy, measurement of Hb A1c, provides a more accurate assessment of long-term glycemia than that obtained from SMBG. The concentration of Hb A1c, which consists of glucose attached to the N-terminal valine of the hemoglobin β …