We aim to understand the impact of HbA1c variability, as measured by SD-HbA1c, on risk of microalbuminuria in T1D population. An analysis was performed utilizing data of 8,680 participants in the T1D Exchange Clinic Registry (50% female, 86% non-Hispanic white, mean age 34 years, mean diabetes duration 14 years at enrollment) who met the following criteria: ≥2 clinic visit records, T1D duration ≥1 year at enrollment, age of diagnosis ≥10 years old and no known renal disease (including no microalbuminuria) at the time of registry enrollment. Median number of albuminuria and HbA1c measures were 4 and 21 per participant, respectively. Microalbuminuria was present during follow-up in 562 (6.5%) participants. Median intrapersonal mean HbA1c and SD-HbA1c were 7.8% and 0.6% respectively. Participants with high HbA1c variability had shorter time to first microalbuminuria (p<0.001, Figure 1a.) Those with high (≥50th percentile) mean HbA1c and high SD-HbA1c also had shorter diabetes duration prior to first reported microalbuminuria compared to high mean-HbA1c but low SD-HbA1c (p<0.001, Figure 1b). HbA1c variability relates to risk of microalbuminuria in T1D; its relationship to other outcomes should be studied.

M.A. Clements: Speaker's Bureau; Self; Medtronic. Advisory Panel; Self; Glooko, Inc.. M. Wu: None. N.C. Foster: None. L.M. Laffel: Consultant; Self; Eli Lilly and Company, Novo Nordisk Inc., Sanofi US, MannKind Corporation, Roche Diagnostics Corporation, Dexcom, Inc., Insulet Corporation, AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Johnson & Johnson Diabetes Institute, LLC.. V.N. Shah: None. F. Vendrame: Consultant; Self; Novo Nordisk Inc.. R.S. Kingman: None. G.T. Alonso: None. A. Carlson: Advisory Panel; Self; Sanofi, Insulet Corporation. Consultant; Self; Merck & Co., Inc.. Research Support; Self; Medtronic, Novo Nordisk A/S. D.J. DeSalvo: Consultant; Self; Dexcom, Inc.. Speaker's Bureau; Self; Insulet Corporation. B.A. Buckingham: Advisory Panel; Self; Novo Nordisk Inc., ConvaTec Inc.. Research Support; Self; Medtronic, Insulet Corporation, Dexcom, Inc., Tandem Diabetes Care, Inc.. Consultant; Self; Tandem Diabetes Care, Inc., Becton, Dickinson and Company. J. Sherr: Consultant; Self; Medtronic MiniMed, Inc.. Advisory Panel; Self; Insulet Corporation, Eli Lilly and Company, Bigfoot Biomedical. R. Benjamin: Speaker's Bureau; Self; Pfizer Inc.. E. Eyth: None. S. DuBose: None.

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