1254-P: Association between Hemoglobin A1c, Time in Range, and Dementia in Veterans with Diabetes Mellitus

Introduction & Objective: Alzheimer's Disease and related dementias (ADRD) are more common in individuals with diabetes. Traditional glycemic measures such as average hemoglobin A1c (A1c) may not capture a dynamic and complex pathophysiology in the relationship between diabetes and ADRD. We developed a measure of glycemic control, A1c time-in-range (TIR), that expresses A1c stability over time within specific ranges and may inform our understanding of the relationship between glucose levels over time and ADRD incidence. The aim of this study is to examine the relationship between A1c TIR and incidence of ADRD in older Veterans with diabetes mellitus. Methods: 374,021 Veterans aged 65 years or older with diabetes during the study period January 1, 2005 to December 31, 2018 were included in this cohort analysis. Individuals with fewer than four A1c tests during a 3-year baseline period (2005-2017), dementia at baseline, or less than 4 years of follow up were excluded. A1c TIR was calculated as the percentage of days during baseline in which A1c was in individualized target ranges based on clinical characteristics and predicted life expectancy, with higher A1c TIR viewed as more favorable. Results: Adjusted Cox proportional hazards models showed that lower A1c TIR was associated with increased risk of incident ADRD (A1c TIR: 0-