1297-OR: Overdiagnosis of Prediabetes by GMI: Use of Updated GMI Improves Alignment with HbA1c and Time Above Range

Introduction and Objective: Glycemic Management Indicator (GMI) is a continuous glucose monitoring (CGM) metric increasingly used to identify prediabetes. However, alignment of this with laboratory glycated hemoglobin (HbA1c) and other CGM metrics varies, especially at lower glucose levels, risking overdiagnosis of prediabetes. We assessed HbA1c-GMI discordance and evaluated a physiological updated GMI (uGMI) for better alignment with HbA1c and time above 140 mg/dL (TA140). Methods: Real-world data from linked LibreView CGM and reference HbA1c were evaluated. GMI used the standard formula while uGMI applied a physiological model. Agreements between HbA1c, GMI, uGMI, and TA140 were assessed via mean-value lines ranked by composite glucose metrics. Results: Among 14,993 individuals with ≥2 paired 56-day CGM and HbA1c values, HbA1c of 5.7% aligned with GMI 6.0%, uGMI 5.6% and TA140 17%. In the normoglycemic range (5.7%; n=801), only 19% had GMI 5.7% vs. 63% with uGMI. Similar but smaller discordance appeared in the prediabetes ranges. TA140 discordance of HbA1c and GMI exceeded 10%, dropping to 3% with uGMI. Conclusion: HbA1c-GMI discordance is common in normoglycemia and prediabetes. uGMI aligns more closely with HbA1c and TA140, improving diagnostic accuracy and glycemic management. Disclosure R. Ajjan: Research Support; Current; Abbott Diabetes. Advisory Panel; Current; Abbott Diabetes. Speaker's Bureau; Current; Abbott Diabetes. Advisory Panel; Ended; Dexcom, Inc. Advisory Panel; Current; Eli Lilly and Company, Insulet Corporation. Speaker's Bureau; Ended; Boehringer Ingelheim International GmbH. Y. Xu: None. T. Dunn: Employee; Current; Abbott Diabetes. P. Choudhary: Advisory Panel; Current; Medtronic. Speaker's Bureau; Current; Medtronic. Research Support; Current; Medtronic. Consultant; Current; Medtronic. Speaker's Bureau; Current; Abbott. Advisory Panel; Current; Abbott. Research Support; Current; Abbott. Speaker's Bureau; Current; Dexcom, Inc. Advisory Panel; Current; Dexcom, Inc. Research Support; Current; Dexcom, Inc. Consultant; Current; Dexcom, Inc. Speaker's Bureau; Current; Insulet Corporation. Advisory Panel; Current; Insulet Corporation. Research Support; Current; Insulet Corporation. Consultant; Current; Insulet Corporation. Speaker's Bureau; Current; Sanofi. Consultant; Current; Sanofi. Speaker's Bureau; Current; Lilly. Advisory Panel; Current; Lilly. Consultant; Current; Lilly. Advisory Panel; Current; Ypsomed AG. Advisory Panel; Ended; Embecta. Speaker's Bureau; Current; Roche Diabetes Care. Research Support; Current; Roche Diabetes Care. Consultant; Current; Roche Diabetes Care. Advisory Panel; Current; Vertex Pharmaceuticals Incorporated. Consultant; Current; Glooko, Inc., Cambridge Mechatronics Ltd, vTv Therapeutics. R.M. Bergenstal: Other - Advisory Panel, Consultant, Clinical Research Support; Current; Abbott Diabetes. Other - Consultant, Clinical Research Support; Current; Dexcom, Inc. Research Support; Current; Amgen Inc. Advisory Panel; Current; CeQur SA. Other - Advisory Panel, Consultant, Clinical Research Support; Current; Eli Lilly and Company. Research Support; Current; Insulet Corporation. Research Support; Ended; Luna. Research Support; Current; Medtronic. Other - Advisory Panel, Consultant, Clinical Research Support; Current; Novo Nordisk. Research Support; Current; Tandem Diabetes Care, Inc. Consultant; Current; Sanofi. Advisory Panel; Current; Vertex Pharmaceuticals Incorporated. Research Support; Current; Zealand Pharma A/S, Sequel, Embecta. Funding Abbott Diabetes Care