Time-in-Range (TIR) Is Suboptimal for Youth with Type 1 Diabetes during School

March, Christine Nanni Michelle Kavanaugh Madison K.; Rothenberger, Scott D.; Siminerio, Linda M.; Miller, Elizabeth Libman Ingrid

Youth with type 1 diabetes spend half their waking weekday hours at school, yet little is known about glycemic control in school. Continuous glucose monitor (CGM) metrics for youth age 7-12 during school hours (8AM-3PM) were compared between weekdays and weekends for 14 days pre COVID-19. Youth with >70% CGM wear (n=214) were identified from a large academic center: 96% white, 46% male, mean (SD) age 10.6 (1.5) years, duration 3.5 (2.5) years, HbA1c 7.5 (0.8) %, 63% with an insulin pump. For weekday school hours, median TIR (70-180 mg/dL) was 52.4%;only 34 (15%) of youth met a TIR goal of >70%. Using random coefficient multilevel linear mixed models, TIR in school was significantly associated with younger age (p=0.008), shorter duration (p<0.001), and lower HbA1c (p<0.001), but not pump use (p=0.42). Weekday and weekend CGM metrics were clinically similar (Table), though TIR was statistically higher (p<0.001) and time high/very high (>180 mg/dL) lower on weekends (p<0.01). Time exhibited a significant fixed and random effect in mixed models;youth with lower TIR at 8AM tended to have larger improvements over subsequent hours. Notably, TIR early in the school day was nearly half of TIR during similar weekend hours, perhaps relating to sleep/meal schedules. Our data support that TIR in school is sub-optimal but may improve while in school, suggesting a benefit to school day routines and opportunity for improving glycemic control in school.