Clinical Use of Hemoglobin A1c to Improve Diabetes Management

F or more than 25 years, the hemoglobin A1c (A1C) test has been the most widely accepted outcome measure for evaluating glycemic control in individuals with diabetes. The test provides an index of a patient's average blood glucose level during the past 2-3 months1 and is considered to be the most objective and reliable measure of long-term metabolic control.2,3 The Diabetes Control and Complications Trial established that maintaining A1C levels as close as possible to the normal range results in considerable reductions in long-term health complications.4 Thus, as the “gold standard” measure of diabetes control, this test provides important feedback to health care professionals and patients. It follows that patients' understanding of this test and its implications for long-term health risk is essential.Research has shown that regular measurement of A1C over the long term can identify patients with poor glycemic control and facilitate their improvement.5 The established relationship between A1C measurements and long-term complications,4 as well as the association between regular A1C testing and improved metabolic control,5 underscore the importance of determining the extent of patients' understanding of this important test and how its results are used in the clinical setting. Patient Knowledge of A1CRelatively few studies have examined diabetic patients' knowledge and understanding of A1C testing. Findings from one recent study conducted in Norway6 revealed that the majority (82.6%) of 201 adult patients with type 1 diabetes knew what their last A1C was, and most patients (90%) knew what a satisfactory A1C value would be. But a significant number of patients (42%) reported they had low knowledge of A1C testing in general. Furthermore, 25% of patients did not think that treatment intensification should occur at an A1C value of 10%.A recent cross-sectional study …