201-OR: Automated Insulin Delivery (AID) System Performance with and Without Meal Announcement: Effect of Meal Macronutrient Content

Missed meal boluses contribute to suboptimal glucose control. There has been limited evaluation of missed boluses for complex or high glycemic index meals while on hybrid closed loop AID systems. Ten subjects with type 1 diabetes (50% male), age 52±10 y, A1C 7.1±0.9%, insulin requirement 0.5±0.2 U/kg/day, used the Lilly investigational AID system (model predictive control algorithm) during a 48 h inpatient observation with 6 meals. For each subject, the 2 breakfast (pancake; [60 g carbohydrate (CHO), 15±4 g fat]) and 2 dinner (pizza; [53±3 g CHO, 20±1 g fat]) meals were identical, and were consumed with or without a pre-meal insulin bolus. Lunch meals were subject-selected (44±16 g CHO, 7±5 g fat), and appropriate pre-meal boluses were administered. Time-in-range (TIR, 70-180 mg/dL) overnight was 99.2±9.5% and following the lunches was 82.1±26.4%. In contrast, TIR following pancake and pizza challenges with bolus were 56.0±34.4% and 65.8±29.6%, and without bolus were 17.8±5.1% and 36.5±25.2%, respectively. Incremental area under the curve (0-2 h) following the pancake meal was larger than the pizza meal within both the bolused and non-bolused scenarios (Table). This study highlights the importance of structured, but varied meal challenge tests in the evaluation of AID system performance. Meal macronutrient content affects AID performance in bolused and non-bolused scenarios. Disclosure A. Bartee: None. R.L. Brazg: None. M. Katz: Employee; Self; Eli Lilly and Company. Stock/Shareholder; Self; Eli Lilly and Company. A. LaLonde: Employee; Self; Eli Lilly and Company. Stock/Shareholder; Self; Eli Lilly and Company. H. Wolpert: Employee; Self; Eli Lilly and Company. R. Jones: Employee; Self; Eli Lilly and Company. Stock/Shareholder; Self; Eli Lilly and Company.