Impact of Glycemic Control on Heart Rate Variability in Youth with Type 1 Diabetes: The SEARCH CVD Study

Abstract Aim: This study explored the role of glycemic control on cardiac autonomic function, measured by heart rate variability (HRV), in youth with type 1 diabetes. Patients and Methods: A retrospective cohort of 345 youth with type 1 diabetes (mean age, 18.5 years; duration, 10 years) participating in the SEARCH for Diabetes in Youth study were enrolled in the ancillary SEARCH Cardiovascular Disease (CVD) study. Anthropometric, metabolic, and HRV parameters were collected at the current research visit. Glycemic control over time was assessed by the mean glycated hemoglobin (A1c) levels collected over the past 6 years. Multiple linear regression analysis assessed the association between A1c over time and HRV parameters, independent of demographic and CVD risk factors. Participants were categorized into four glycemic control categories based on their mean A1c over time: Group 1, optimal (mean A1c, ≤7.4%); Group 2 (mean A1c, 7.5–8.4%); Group 3 (mean A1c, 8.5–9.4%), and Group 4, poor (mean A1c, ≥9.5%), and...