A discrepancy between laboratory-measured HbA1c and Glucose Management Indicator (GMI), estimated from continuous glucose monitoring, is frequently encountered in clinical practice. However, its evolution over time is not yet known.

Methodology: We conducted a multicenter retrospective study (9 centers) that collected pairs of HbA1c and GMI (calculated over 90 days) at T0, T1 year, T2 years of follow-up in patients with diabetes, all users of FreeStyleLibre®. The primary study endpoint was the analysis of the mean HbA1c-GMI differences at the 3 time points. Glucose data, clinical parameters, and complications were also analyzed. Patients were classified based on the HbA1c-GMI discrepancy: positive (PosD, HbA1c-GMI>+0.3%), neutral (NullD, HbA1c-GMI from -0.3 to +0.3%), negative (NegD, HbA1c-GMI< -0.3%) at each time point, and with the average differences over the 3 time points. Group comparisons were assessed using ANOVA.

Result: We included 347 patients (82% type 1 diabetes), mean age of 51±17 years, diabetes duration 20±13 years, HbA1c 7.6±1.0%, 90±9% CGM data collected, Time in Range 70-180 mg/dl (TIR) 57±17%, GMI 7.4±0.8%. The mean HbA1c-GMI differed over time (T0: 0.27%, T1 year: 0.16%, T2 years: 0.04%, P<0.0001). Considering the mean HbA1c-GMI differences over the 3 time points for all patients, PosD individuals were statistically older, had higher BMI and HbA1c compared to NegD patients. At T0, the patients were distributed as follows: 168 PosD (48.4%), 129 NullD (37.2%), 50 NegD (14.4%). The 121 patients (only 34.8% of the cohort) who stayed in the same group at the three time-points were 44.6% PosD, 38% NullD and 17.4% NegD.

Conclusion: In only 1/3 of patients does the difference between HbA1c and GMI appear to be stable over time. This should be taken into account when analyzing the supposed poor prognosis associated with PosD.

Disclosure

J. Riveline: Board Member; Abbott, Novo Nordisk A/S, Sanofi, Eli Lilly and Company, Medtronic, Dexcom, Inc., Insulet Corporation, Air Liquide, AstraZeneca. G. Prevost: Board Member; Abbott. A. Andrieu: None. M. Joubert: Consultant; Abbott, Medtronic, Dexcom, Inc. P. Oriot: Research Support; Abbott. A. Penfornis: Speaker's Bureau; Sanofi, Dexcom, Inc., Diabeloop SA. Board Member; AstraZeneca. Speaker's Bureau; Novo Nordisk, Lilly Diabetes. Board Member; Novo Nordisk, Bayer Inc. Advisory Panel; Abbott, Sanofi. J. Philips: Consultant; Sanofi, Novo Nordisk, Abbott, Avazzia, Boehringer-Ingelheim, Eli Lilly and Company. J. Julla: Speaker's Bureau; Lilly Diabetes, Novo Nordisk. Board Member; Sanofi. E. Cosson: Advisory Panel; Abbott, AstraZeneca, Lilly Diabetes, Novo Nordisk, Sanofi, Roche Diagnostics, Novartis AG, Amgen Inc.

Funding

Abbott Diabetes Care

© 2024 by the American Diabetes Association
2024
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