An Assessment of Meal Anticipation for Improving Fully Automated Insulin Delivery in Adults with Type 1 Diabetes

Objective: Meals are a consistent challenge to glycemic control in type 1 diabetes (T1D). Our objective was to assess the glycemic impact of meal anticipation within a fully automated insulin delivery (AID) system among adults with T1D.

Research Design and Methods: We report the results of a randomized-crossover clinical trial comparing three modalities of AID systems: hybrid closed-loop (HCL), full closed-loop (FCL), and full closed-loop with meal anticipation (FCL+). Modalities were tested during three supervised 24h admissions, where breakfast, lunch, and dinner were consumed per participant’s home schedule, at a fixed time, and 1.5h delayed, respectively. Primary outcome was the percent time-in-range 70-180mg/dL (TIR) during the breakfast post-prandial period for FCL+ vs. FCL. 

Results: Thirty-five adults with T1D (age 44.5±15.4y; HbA1c 6.7±0.9%; 23F/12M) were randomized. TIR for the 5h-period following breakfast was 75±23%, 58±21%, and 63±19%, for HCL, FCL, and FCL+ respectively, with no significant difference between FCL+ and FCL. For the 2h before dinner TBR was similar for FCL and FCL+. For the 5h-period following dinner TIR was similar for FCL+ and FCL (71±34% vs. 72±29%; p=1.0) while TBR was reduced in FCL+ (median: 0 [0-0]% vs. 0 [0-0.8]%;p=0.03). Overall, 24-h control for HCL, FCL and FCL+ was 86±10%, 77±11%, and 77±12%, respectively.

Conclusions: While postprandial control remained optimal with hybrid AID, both fully AID solutions offered overall TIR above 70% with similar or lower exposure to hypoglycemia. Anticipation did not significantly improve postprandial control in AID systems but also did not increase hypoglycemic risk when meals were delayed.