Maintaining blood glucose (BG) control among adolescents with Type 1 diabetes (T1D) is arguably the greatest challenge in the entire field of T1D. One reason for this poor control relates to missed meal boluses, which affects 65% of adolescents at least once weekly, with 38% missing at least 15% of their boluses. Adolescents who miss four boluses weekly experience an increase of 1% in their HbA1c. While the advent of the artificial pancreas (AP) offers promise of safe reductions in HbA1c, the study team previously found that the AP only partly compensates for missed prandial insulin -demonstrating that some form of meal announcement is necessary for good BG control, even with an AP. One way to automate this process is by sharing the prandial dosing responsibilities between an automated insulin priming (based on continuous glucose monitor condition predictive of a safe situation for such insulin dosing) and a closed loop controller capable of reconstructing (estimating) the prevailing glucose rate of appearance from an unannounced meal. The study team has developed such an insulin priming schema and integrated it into a new version of the robust Model Predictive Controller University of Virginia AP system (called the RocketAP).~In the current study, the investigators are testing this new AP system in two configurations: hybrid and fully automated, among up to 20 adolescents. The primary outcome will be one of efficacy in assessing how well the new system controls post-prandial BG in the absence of carbohydrate (CHO) announcement as compared to the same situation but using the Control-IQ closed loop algorithm, also designed at UVa and using the same modular architecture and safety system, but without insulin priming and with a less advanced model-based controller. Further comparisons will be made to BG control on RocketAP with CHO announcement and on Control-IQ with CHO announcement. Adolescents will be started on the respective University of Virginia AP systems (RocketAP and Control-IQ in random order, both implemented on the DiAs platform, MAF 2109) and followed over the course of two dinners on each of the two platforms: a dinner where CHO is announced as normal and the 2nd where no announcement is made.~The study team hypothesize that performances of RocketAP in fully automated mode will lie in between Hybrid and Fully Automated Control-IQ. In time, this may provide an opportunity to improve BG control among adolescents who miss meal announcement.
The study team will be comparing two investigational Artificial Pancreas (AP) systems that the UVA Center for Diabetes Technology has developed. An artificial pancreas system delivers insulin automatically based on a blood glucose level that is provided from a continuous glucose monitor (CGM).