Future of Automated Insulin Delivery Systems

Abstract

Advances in continuous glucose monitoring (CGM) have brought on a paradigm shift in the management of type 1 diabetes. These advances have enabled the automation of insulin delivery, where an algorithm determines the insulin delivery rate in response to the CGM values. There are multiple automated insulin delivery (AID) systems in development. A system that automates basal insulin delivery has already received Food and Drug Administration approval, and more systems are likely to follow. As the field of AID matures, future systems may incorporate additional hormones and/or multiple inputs, such as activity level. All AID systems are impacted by CGM accuracy and future CGM devices must be shown to be sufficiently accurate to be safely incorporated into AID. In this article, we summarize recent achievements in AID development, with a special emphasis on CGM sensor performance, and discuss the future of AID systems from the point of view of their input-output characteristics, form factor, and adaptability.

Keywords: Artificial pancreas; Continuous glucose monitoring; Type 1 diabetes.

FIG. 1.

There exists a curvilinear relationship between MARD and the frequency of large deviations (>20%). Analyses of CGM accuracy data done by multiple studies show that this curve holds for a variety of sensors and is invariant across sensor manufacturers. Extensive in silico studies indicate that, within the rectangular area defined by MARD <10% and large deviations <12%, further improvement in sensor accuracy does not contribute substantively to better glycemic outcomes. Thus, a sensor with accuracy within this rectangular area can be used as replacement for blood glucose meters. The sensors depicted in the figure include: (1) Medtronic Paradigm with Enlite sensor; (2) Medtronic Paradigm with Enlite sensor; (3) Animas Vibe with Dexcom G4 version A; (4) Freestyle Navigator I; (5) Freestyle Navigator II; (6) Dexcom G4 Platinum; (7) Dexcom G4 Platinum; (8) Dexcom G5 with software 505. CGM, continuous glucose monitoring; MARD, mean absolute relative difference.