165-OR: Improving A1C and CGM Average Glucose Alignment—The Updated Glucose Management Indicator (GMI)

Introduction and Objective: The not-infrequently observed disconnect between A1C and GMI, particularly at low and high A1C levels, can create clinical management difficulties. Our aim was to evaluate the agreement of an updated GMI metric (uGMI) with A1C and potential use in diabetes management. Methods: The GDAC study (n=257) collected CGM data and bi-monthly A1C for 26 weeks for those with diabetes across different race groups. GMI was calculated by an empirical known formula employing average glucose (AG) levels, GMI(%)=0.02392*AG+3.31, while the uGMI formula accounts for population-based red blood cell factors, uGMI(%) = (15.36/AG+0.0426)-1. Analysis was replicated in a real-world dataset (n=2,074). Results: GDAC showed a disconnect between original GMI and A1C with regression slope value up to 25% outside unity, a difference more pronounced in the Black group at 40%. Using uGMI, regression slopes improved to within 2 and 6% of unity in the non-Black and Black groups, respectively. For the same AG, the Black group displayed higher A1C values than the non-Black group, at all HbA1c ranges.The misalignment between GMI and A1C was more pronounced in real-world data with values up to 50% outside unity, improving to within 3% of unity with uGMI. Conclusion: The uGMI metric is superior to the original GMI at reflecting A1C, promising to refine interpretation of CGM data and improve clinical decision-making. R.M. Bergenstal: Advisory Panel; Abbott. Research Support; Abbott. Consultant; Abbott. Research Support; Dexcom, Inc. Consultant; Dexcom, Inc., Eli Lilly and Company. Research Support; Eli Lilly and Company. Consultant; Novo Nordisk. Research Support; Novo Nordisk. Consultant; Roche Diabetes Care, Sanofi, Medtronic. Research Support; Medtronic, Insulet Corporation, Hemsley Charitable Trust. Other Relationship; MannKind Corporation. Consultant; Medscape. Research Support; National Institute of Diabetes and Digestive and Kidney Diseases, Tandem Diabetes Care, Inc, UnitedHealth Group. Consultant; Vertex Pharmaceuticals Incorporated, Ascensia Diabetes Care, American Diabetes Association, Hygieia, embecta, Senseonics, Zealand Pharma A/S. Y. Xu: Employee; Abbott. T. Dunn: Employee; Abbott. Other Relationship; Omada Health. P. Choudhary: Speaker's Bureau; Abbott. Advisory Panel; Dexcom, Inc. Consultant; Insulet Corporation. Advisory Panel; Ypsomed AG, embecta, Sanofi. Speaker's Bureau; Lilly Diabetes, Medtronic. Advisory Panel; Roche Diabetes Care. Consultant; Cambridge Mechatronics. R. Ajjan: Research Support; Abbott. Speaker's Bureau; Abbott, Boehringer-Ingelheim. Advisory Panel; AstraZeneca, Novo Nordisk.