Hybrid Closed-loop therapy: Where are we in 2021?

Abstract

Hybrid closed-loop systems are characterised by the coexistence of algorithm driven automated insulin delivery combined with manual mealtime boluses. Used correctly, these insulin delivery systems offer better glucose control and reduced risk of hypoglycemia and represent the most advanced form of insulin delivery available for people with type 1 diabetes. This paper aims to compare the currently available commercial hybrid closed-loop systems in the UK: Medtronic 670G/780G, Tandem t:slim X2 Control IQ and CamAPS FX systems. Medtronic 670G/780G systems use Guardian 3 sensor (7 day use, two to four calibrations / day) while Tandem and CamAPS systems use the calibration free Dexcom G6 sensor (10 days). CamAPS system is available as an android app while other two systems have the algorithm embedded in the insulin pump. During pivotal studies, depending on the study population and baseline HbA1c, these systems achive % time spent in the target range 3.9 to 10 mmol/l (70 to 180mg/dl) from 65% to 76% with low burden of hypoglycemia. All three systems allow for a higher glucose target for announced exercise while the Tandem system offers an additional night time tighter target. The CamAPS system offers fully customisable glucose targets and is the only system licenced for use during pregnancy. Additional education is required for both users and healthcare professionals to harness the best performance from these systems as well as trouble shoot when 'auto-mode'exists occur. We provide consensus recommendations to develop pragmatic pathways to guide patients, clinicians and commissioners in making informed decisions on the appropriate use of the diabetes technology.