159-OR: Greater Sleep Variability Is Associated with Less Time in Range of Glucose Levels in Patients with Type 1 Diabetes

Background: Sleep and circadian disturbances emerge as novel factors influencing glycemic control in type 1 diabetes (T1D). We aimed to explore the associations between sleep, behavioral circadian parameters, self-care, and glycemic parameters in T1D.

Methods: Baseline data of 76 non-shift working adult T1D patients participating in a randomized study to optimize sleep health (NCT04506151) were analyzed. Glycemic assessments were derived from blinded 7-day continuous glucose monitoring (CGM) and A1C. Percentages of time-in-range (TIR of glucose levels between 70-180 mg/dL) and %CV were calculated from CGM. Sleep was recorded using 7-day actigraphy, yielding sleep duration and efficiency. Variability (SD) of mid-sleep time (MST) was used to represent sleep variability. Non-parametric behavioral circadian variables were derived from actigraphy activity recordings. Self-care was measured by the Diabetes Self-Management Questionnaire (DSMQ-R). Multiple regression analyses were performed to identify independent predictors of glycemic parameters.

Results: Mean (SD) age was 36.3 (11) years, 48 (63.2%) female, and median (IQR) A1C 6.8% (6.2, 7.4). Sleep duration, efficiency, and non-parametric behavioral circadian variables were not associated with glycemic parameters. After adjusting for age, sex, insulin delivery mode/CGM use, and ethnicity, each hour increase in SD of MST was associated with 9.64 % less TIR (B= -9.64, 95% (CI) [-16.29, -2.99], p=<0.001). Higher DSMQ score was an independent predictor of lower A1C (B = -0.18, 95% CI -0.32, -0.04).

Conclusion: Greater sleep variability is independently associated with less time spent in desirable glucose range in this modern T1D cohort, with clinically important effect sizes. Sleep optimization to reduce variable sleep schedule could potentially lead to improved metabolic control and should be explored in future research.