Open source artificial pancreas systems: to use or not to use

There has been huge progress over the past decade towards realising the goal of an artificial pancreas, freeing those with type 1 diabetes from the day-to-day chore of trying to maintain relatively normal blood glucose levels to improve their quality of life and minimise the risk of complications. Insulin pumps have been capable of delivering insulin subcutaneously at variable rates for many years, but it is only recently that continuous glucose monitoring using sensors measuring interstitial glucose has become reliable enough to allow the automation of insulin delivery according to sensor glucose readings. 

Medtronic’s MiniMed 640G system employs a predictive low glucose suspend function to effectively minimise hypoglycaemia risk – a life-changing technology for those with loss of hypoglycaemia awareness. The similar Tandem t:slim X2 and Medtrum A6 TouchCare systems are now available, although clinical experience with the latter is limited. Medtronic’s more recent 670G system, available in the US for over 2 years and now the UK and Europe, is a hybrid closed-loop system that adjusts insulin delivery automatically as glucose levels change, with meal announcement allowing appropriate bolus dosing for the amount of carbohydrate entered into the system’s bolus calculator. In research settings, closed-loop systems have been safely and effectively tested with insulin alone, or with glucagon – and even pramlintide – in different groups, including children and pregnant women, and in different settings. 

For the person with type 1 diabetes, the frustration has been the lack of availability of closed-loop products when the requisite insulin pump and glucose-sensing components have been available and fit for purpose for a number of years. This frustration has been manifest in the #WeAreNotWaiting movement, which has been active since 2013. Members of this group, consisting of people with type 1 diabetes and parents of affected children, have developed software algorithms to allow certain commercially-available insulin pumps and continuous glucose sensors to be combined in a closed-loop system. These OpenAPS – open source artificial pancreas systems – have been available since 2015 and there are a small but increasing number of UK users, mostly using DANA or Roche pumps with Dexcom sensors. These systems are unregulated, so concerns remain about the validity of some warranties when components are used in these systems and legal responsibility should users of these systems come to harm from system malfunction if healthcare professionals know they are using them. While some OpenAPS enthusiasts have been very vocal in extolling the benefits and lack of risk with such systems, there has been no systematic data collection or reporting to substantiate these claims. 

Unsurprisingly for a movement that began with a hashtag, one of the best sources of information and feedback about OpenAPS systems comes from Twitter. Litchman et al have harnessed this information source to produce an analysis, summarised in our Digest here, supporting the suggested benefits of OpenAPS systems. The nature of the information source means that this analysis is qualitative, but the authors were able to identify common themes from the 328 users or their carers/parents including:

• OpenAPS changes lives
• OpenAPS use suggests self-reported improvement in HbA1c and glucose variability 
• OpenAPS improves sense of diabetes burden and improves quality of life
• OpenAPS is perceived as safe.

This presents healthcare professionals with a challenge. We will naturally want to support those wanting to use OpenAPS in our services because the technology delivers such benefits, but what about ethical and medicolegal concerns related to the use of an unregulated user-developed and -driven system? In the related commentary, Barnard et al consider the various issues related to supporting OpenAPS users. This should assist diabetes teams in deciding whether or how best to support people with type 1 diabetes considering or using OpenAPS.

It is unrealistic to expect widespread NHS funding for commercially-available hybrid closed-loop systems such as 670G in the short term, so we can expect there to be a lot more interest in OpenAPS in the UK in the next few years. We need to be able to support those who are able to use OpenAPS systems effectively, while cautioning those who may not be suited to such systems, for whom alternative interventions may be more beneficial. We need to establish some ground rules for supporting OpenAPS users and start systematically collecting data to further support the evidence of benefit and safety indicated by the Twitter analysis. The publications by Litchman et al and Barnard et al are timely in helping facilitate debate among UK diabetes healthcare professionals. 

Click the links below to access the latest Diabetes Digests related to devices and technology:

• Twitter analysis suggests OpenAPS improves patients’ lives
• Insulin pump treatment (INPUT) education programme improves glycaemic control in CSII patients
• Measurement accuracy of blood glucose monitoring versus continuous glucose monitors
• Closed-loop systems improve glycaemic control in inpatients with type 2 diabetes

Reference
Barnard KD, Ziegler R, Klonoff DC et al (2018) Open source closed-loop insulin delivery systems: a clash of cultures or merging of diverse approaches? J Diabetes Sci Technol 12: 1223–6