In a recent review by Boughton and Hovorka the most recent (soon-to-be) commercially available closed-loop systems are discussed.
Technical developments in the treatment of type 1 diabetes are moving fast. Administering insulin by pump (continuous subcutaneous insulin infusion or CSII) has been routinely used since the 1980s, initially only for people with type 1 diabetes whose glucose regulation was difficult to manage. In the 1990s many of the initial technical problems were resolved and insulin pumps were increasingly used in routine type 1 diabetes care. Click here for a nice overview on the evolution of insulin pumps: from a large, unwieldy machine carried on your back to small, pager-size devices.
For a long time the only way to monitor blood glucose was by capillary blood glucose monitoring (i.e. finger pricking and blood glucose meter with test strips). Since the early 2000s the use of continuous blood glucose monitoring (CGM) has increased. Click here for a nice review on the history of CGM. CGM provides a much more detailed view of blood glucose profiles, allowing better guidance of insulin administration (a.k.a. sensor-augmented pump [SAP] treatment). The holy grail has for a long time been to connect the insulin pumps and CGM devices to create an automatic system or ‘artificial pancreas’, either using only insulin or both insulin and glucagon. Initially the loop between pump and CGM was semi-closed, meaning that the pump suspends insulin administration when blood glucose is predicted to decrease too much (predicted low-glucose suspend or PLGS).
As Boughton and Hovorka describe, recently hybrid closed-loop (HCL) and advanced hybrid closed-loop (aHCL) systems have become commercially available, allowing the users to have more ‘time off’ from their disease. Also there is an online community of people with diabetes who are connecting (‘looping’) their pumps and CGM devices themselves (the #wearenot waiting movement). However, these systems still require a fair amount of their users’ input to remain in automode. Therefor education is of paramount importance. As we have presented recently at EASD 2020, Diabeter’s comprehensive and structured education and an extended support and follow-up program result in >80% time in automode among users of the Medtronic 670G HCL system. Click here for the presentation. We have also already done a pilot study with the 780G aHCL system, allowing users even more ‘time off’. The results of this study are very promising and have been submitted to ATTD 2021. Further evaluation of real-life use of this system is currently being planned.
Boughton and Hovorka conclude that during the last few years closed-loop systems have been successfully been transferred from research to routine type 1 diabetes care. However, improvements with regard to glucose control around meals and exercise and useability are still needed to really lighten the burden of the disease.