Understanding the association between glycemia and A1c by race can improve screening for prediabetes and type 2 diabetes (T2D) . This association was examined cross-sectionally in 1016 Black and 2658 White persons screened for D2d (mean age 60; fasting glucose [FG] 1mg/dL; A1c 5.9%) . Of these, 22with at least 2-of-3 ADA glycemic criteria for prediabetes (mean age 60, FG 1mg/dL, A1c 5.9%, 28% Black) were followed longitudinally for median 2.5 years with annual OGTT and semi-annual FG and A1c. Numerical integration methods were used for the estimation of area under the OGTT-derived glucose curve (AUC) . Mean A1c was estimated for a given AUC quintile using linear regression for Whites, Blacks, and Asians. Adjusting for covariates, the A1c was higher by 0.2-0.25% among Black vs. White participants with similar glycemia in all AUC quintiles. During follow-up, Black participants were more likely to be diagnosed with T2D based on A1c; White participants were more likely to be diagnosed by FG. The absolute increase in A1c over time according to baseline AUC-glucose quintiles differed by race. Compared to White participants, Black participants in lower baseline AUC quintiles had greater increases in A1c over time, while A1c increased similarly in White and Black persons in the two highest baseline AUC quintiles.
In summary, Black participants had higher A1c than White participants for similar degree of glycemia defined by AUC; the glycemic criteria contributing to the diagnosis of T2D differed by race; and there were AUC by racial interactions in A1c increase over time.
E.S.Leblanc: n/a. S.Dagogo-jack: Consultant; AstraZeneca, Bayer AG, Boehringer Ingelheim International GmbH, Janssen Pharmaceuticals, Inc., Medtronic, Merck & Co., Inc., Sanofi. J.P.Nelson: None. D.S.Hsia: None. D2d research group: n/a. A.G.Pittas: None. R.Chatterjee montgomery: Research Support; Bristol-Myers Squibb Company, Epigenomics AG. N.Rasouli: Advisory Panel; Eli Lilly and Company, Novo Nordisk, Sanofi, Research Support; Allergan, Eli Lilly and Company, Novo Nordisk. M.K.Rhee: Research Support; Kowa Company, Ltd. R.E.Pratley: Other Relationship; Bayer AG, Corcept Therapeutics, Dexcom, Inc., Hanmi Pharm. Co., Ltd., Merck & Co., Inc., Metavention, Novo Nordisk, Pfizer Inc., Poxel SA, Sanofi, Scohia Pharma Inc., Sun Pharmaceutical Industries Ltd. C.Desouza: Advisory Panel; AstraZeneca, Bayer AG, Novo Nordisk A/S, Consultant; Asahi Kasei Corporation. L.M.Neff: Employee; Eli Lilly and Company, Research Support; Amryt Pharma Plc, Novo Nordisk, Stock/Shareholder; Eli Lilly and Company. A.L.Peters: Advisory Panel; Abbott Diabetes, AstraZeneca, Eli Lilly and Company, Novo Nordisk, Shouti, Vertex Pharmaceuticals Incorporated, Zealand Pharma A/S, Other Relationship; Omada Health, Inc., Research Support; Abbott Diabetes, Dexcom, Inc., Insulet Corporation, Leona M. and Harry B. Helmsley Charitable Trust, Stock/Shareholder; Teladoc Health.
American Diabetes Association (1-14-D2d-01) ; National Institutes of Health National Institute of Diabetes and Digestive and Kidney Diseases and Office of Dietary Supplements (U01DK098245)