Recent advances in closed-loop insulin delivery

Abstract

Since the discovery of insulin 100 years ago, we have seen considerable advances across diabetes therapies. The more recent advent of glucose-responsive automated insulin delivery has started to revolutionise the management of type 1 diabetes in children and adults. Evolution of closed-loop insulin delivery from research to clinical practice has been rapid, and multiple systems are now commercially available. In this review, we summarise key evidence on currently available closed-loop systems and those in development. We comment on dual-hormone and do-it-yourself systems, as well as reviewing clinical evidence in special populations such as very young children, older adults and in pregnancy. We identify future directions for research and barriers to closed-loop adoption, including how these might be addressed to ensure equitable access to this novel therapy.

Keywords: Artificial pancreas; Closed loop insulin delivery; Diabetes technology; Type 1 diabetes.

Figure 1.. Commercially available hybrid closed-loop systems.

Control algorithms for closed-loop insulin delivery. Panel A is a diagram of a simple proportional integral derivative (PID) controller (adapted from Lal et al [79]); Panel B is a graphical representation of a simplified model predictive controller (MPC) (adapted from Wang et al [80]); Panel C is an example of a fuzzy logic controller using current sensor glucose level, rate of change and acceleration in sensor glucose (adapted from Mauseth et al [81]).

Figure 2.. Commercially available hybrid closed-loop systems.

(a) Medtronic 670G Hybrid Closed Loop System with Guardian Link 3 transmitter and the COUNTOUR NEXT LINK blood glucose meter and (b) Medtronic 780G Advanced Hybrid Closed Loop System (reproduced with permission of Medtronic, Inc.) (c) DBLG1 hybrid closed-loop system with Kaleido insulin patch-pump and Dexcom G6 CGM (Dexcom, San Diego, CA, USA) (reproduced with permission of Diabeloop SA) (d) CamAPS FX algorithm with Dexcom G6 sensor and Dana Diabecare RS and Dana-i insulin pumps (Sooil Development, Seoul, Korea) (reproduced with permission of CamDiab Ltd) (e) Tandem t:slim X2 insulin pump (Tandem Diabetes Care, San Diego, CA, USA) paired with a Dexcom G6 Sensor (Dexcom, San Diego, CA, USA) (reproduced with permission).