Managing discordance between <scp> HbA <sub>1c</sub> </scp> and glucose management indicator
Erna Lenters‐Westra, Marion Fokkert, Eric S Kilpatrick, Erwin Schleicher, Scott J. Pilla, Emma English, Peter R. van Dijk
Abstract
Abstract Aims The assessment of haemoglobin A1c (HbA 1c ) continues to play an essential role in diabetes care; however, major advances in new technologies widen the armament available to clinicians to further refine treatment for their patients. Whilst HbA 1c remains a critical glycaemic marker, advances in technologies such as Continuous Glucose Monitoring (CGM) now offer real‐time glucose monitoring, allowing a more instant assessment of glycaemic control. Discrepancies between laboratory‐measured HbA 1c and Glucose Management Indicator (GMI) values are a significant clinical issue. In this article, we present a checklist of potential sources of error for both GMI and HbA 1c values and provide suggestions to mitigate these sources in order to continue to improve diabetes care. Methods We identified key literature pertaining to GMI measurement, HbA 1c measurement, and potential factors of discordance between the two. Using these sources, we explore the potential factors leading to discordance and how to mitigate these when found. Results We have constructed a quick reference checklist covering the main sources of discordance between HbA 1c and GMI, with accompanying narrative text for more detailed discussion. Discordance can arise due to various factors, including CGM accuracy, sensor calibration, red blood cell turnover and other physiological conditions. Conclusions GMI will likely continue to be used in the upcoming years by both persons with diabetes and their health care providers, and so it is important for users of CGM devices to be equipped with the knowledge to understand the potential causes of discordance between GMI and HbA 1c values.