676-P: Difference in CGM Estimated Hemoglobin A1c in Adults with Type 1 and Type 2 Diabetes

The relationship between mean glucose measured using a continuous glucose monitor (CGM) and hemoglobin A1c (A1C) was evaluated in adults with type 1 diabetes (T1D) or type 2 diabetes (T2D) . Data from participants enrolled in the MOBILE, DIAMOND, and WISDM trials and randomized to the CGM arm were used in the analysis. Follow-up visits collected A1C measured by a central laboratory at 8 months post-randomization in the MOBILE study and 6 months post-randomization in DIAMOND and WISDM studies. CGM data collected in the 91 days prior to the follow-up visit, when glucose control was thought to be relatively stable, was used to compute mean glucose. A least squares linear regression model estimated A1C using mean glucose as a predictor, and models were fit separately by diabetes type. 199 participants with T1D and 175 participants with T2D were included in the analysis. Mean age was 57±15 years among those with T1D and 58±years among those with T2D. Estimated A1C was similar but slightly higher for participants with T2D vs. T1D for the same mean glucose (Table) . Analyses restricting to White non-Hispanic cohort yielded similar results. Spearman partial correlation coefficients for mean glucose vs. A1C were 0.76 for T1D and 0.84 for T2D. Estimates of A1C based on CGM measured mean glucose were slightly higher for those with T2D compared with T1D. Disclosure M.Salam: Advisory Panel; Lilly Diabetes, Consultant; Neurocrine Biosciences, Inc., Research Support; Mylan N.V., Neurocrine Biosciences, Inc. R.Bailey: None. P.Calhoun: None. J.B.Mcgill: Advisory Panel; Gilead Sciences, Inc., Lilly Diabetes, MannKind Corporation, Novo Nordisk A/S, Provention Bio, Inc., Salix Pharmaceuticals, Consultant; Bayer AG, Boehringer Ingelheim International GmbH, Research Support; Dexcom, Inc., Novo Nordisk. R.Beck: Consultant; Diasome, Eli Lilly and Company, Insulet Corporation, Novo Nordisk, Research Support; Ascensia Diabetes Care, Beta Bionics, Inc., Bigfoot Biomedical, Inc., Dexcom, Inc., Eli Lilly and Company, Medtronic, Novo Nordisk, Roche Diabetes Care, Tandem Diabetes Care, Inc. D.A.Price: Employee; Dexcom, Inc.