2766-LB: Meal Logging Behaviour and Glycemic Control in Users of the Loop Automated Insulin Delivery System

Introduction and Objective: Manual meal management is a major challenge for people with diabetes. This study examined whether personalized prior meal records improve postprandial glucose forecasting and reduce user burden. Methods: In a 40-day observational study, 28 adults using the open-source Loop Automated Insulin Delivery system logged meals under free-living conditions. Participants self-identified behavioral strategies as “Accurate Carb-Counting” (57%), “Approximate Carb-Counting” (32%), or “Mixed logging” (11%). Postprandial Time in Range (TIR) was calculated for each meal as the percentage of glucose values within 70-180 mg/dL during the 3-h postprandial window. Meals were categorized as Singleton or Repeated, where Singleton meals comprised 41% of entries. Results: During the initial 1926 meals, participants demonstrated high engagement with a mean of 5.1 entries per day. Behavioral diversity was evident: “Accurate”, “Approximate”, and “Mixed” loggers averaged 5.8, 4.9, and 2.9 entries per day, respectively. Meal repetition increased over time, and repeated meals were associated with higher post-prandial TIR than singletons (p=0.0097), regardless of the meal logging strategy. Conclusion: Across diverse logging behaviors, repeated meals correlate with improved post-prandial TIR, suggesting that personalized dosing strategies can reduce the burden of manual meal management. Disclosure S.F. Royston: Stock/Shareholder; Current; Replica Health Cop. M.K. Wolff: Consultant; Current; Replica Health Cop. S. Khan-Gallo: Employee; Current; Tidepool. M. Friedman: Employee; Current; Tidepool. C. Brydges: Employee; Current; Tidepool. R. Lal: Consultant; Current; Abbott Diabetes, Adaptyx Biosciences. Consultant; Ended; Biolinq, Capillary Biomedical, Deep Valley Labs. Consultant; Current; Gluroo, Portal Diabetes, Tidepool. Advisory Panel; Ended; ProventionBio, Lilly, Sanofi, Rezolute.