People with type 1 diabetes have been dreaming for decades that their blood sugar automatically regulates as in healthy people. Automatic systems that work like a pancreas are not yet officially available. A handful of tech-savvy diabetics did not want to wait for this. In their own responsibility, they have developed artificial pancreas, so-called closed-loop systems (also called Artifical-Pancreas-Systems, short APS). They each consist of glucose meter, smartphone app and compatible insulin pump.
Work on such a system began in 2014 for US-American Dana M. Lewis – since her teenage diabetic – and her life partner, molecular biologist Scott Leibrand. Both were dissatisfied with officially available diabetes aids. They wanted to expand existing systems. Together with other open source developers, they introduced the first closed-loop platform OpenAPS. Initially, the number of users was manageable, which was mainly due to high technical hurdles. Thanks to sophisticated documentation and simplified handling, there are now several thousand “Looper” worldwide. They use the hashtag #WeAreNotWaiting to exchange information on Internet platforms and social media.
Even with current medical technology is still the patient’s main player in the blood sugar management: It reads current glucose levels on his meter and changes if necessary, the amount of insulin, which delivers his insulin pump. Closed-loop systems help patients make the right choice of insulin in many situations.
What do closed-loop systems do?
Closed-loop systems adjust the insulin delivery as needed. Among other things, the software takes into account deviations from previously measured values, current insulin in the body, the adjusted blood sugar target value and carbohydrates taken over meals, in addition to current glucose values.
Without manual interventions, you can not get out of here, which is why it is better to talk about “hybrid closed-loop systems”. Since the system can not anticipate meals, it is necessary to switch on the insulin delivery of the pump before eating. The patient is also in demand for special activities: In sports, for example, it may be useful to increase the blood sugar target value temporarily to avoid hypoglycaemia.
Current DIY systems at a glance
The forerunner of the closed-loop systems is the OpenAPS mentioned at the beginning. It only works with older Medtronic insulin pumps. The software runs on a mini-computer with Linux. Because Medtronic insulin pumps use proprietary wireless connectivity, additional hardware is needed to convert the wireless signal to Bluetooth Low Energy for connection to the mini-computer.
OpenAPS has no graphical user interface. For example, with the cloud-based Nightscout tool, you can graphically edit the data and operate OpenAPS.
AndroidAPS uses the same algorithm as OpenAPS and also communicates with Nightscout. However, no mini-computer is required here – the software runs as an Android app. Because the supported insulin pumps (AccuCheck Combo, AccuCheck Insight, and Dana Diabecare RS) use Bluetooth for communication, unlike OpenAPS, no other hardware is required except the smartphone, an insulin pump, and the meter. For this you still need the app Xdrip +, which is available for download at GitHub as an APK. It processes sensor data and passes the values to AndroidAPS. In the future, AndroidAPS should also support Medtronic insulin pumps. This would make the selection of insulin pumps very extensive.
The closed loop system Loop is available as an iPhone app. As it only supports some Medtronic insulin pumps that are no longer available, such as OpenAPS, the so-called Riley link for converting the radio signals is required here as additional hardware. Unlike AndroidAPS, Loop comes with a sleek, clean interface, but it lacks advanced features.
Since the app is not in the App Store, you have to go to install a detour. Users need to build a working app using Apple Xcode and a free Apple Developer account. So resulting developer versions are only partially executable, you have to renew them every seven days. If you have a paid Developer account instead, this is only necessary once a year. In the near future, Loop will be the first closed loop system to support the popular insulin pump Omnipod from Insulet.
Closed loop in the self-test
There were two sticking points where I hoped for improvements through a closed-loop system. At night I had frequent, but irregularly with blood sugar spikes to fight. In addition, there were strong blood sugar increases after sports. The installation and setup of AndroidAPS was easy, thanks to detailed and comprehensible documentation in German: After installing the Android Studio development environment, GitHub will download the AndroidAPS project files and compile them into an APK file. You then move it to the smartphone and install it. To do this, you have to share the installation of apps from external sources. This can be undone after installation. In addition, you need the app Xdrip +, which processes the blood glucose values from the CGM system. AndroidAPS guides users through the most important settings. The entire process took just under one and a half hours.
A special feature of AndroidAPS are the objectives: To begin with, users have to meet goals over several weeks in order to unlock functions. For example, you have to set the system to spend one night without hypoglycaemia and keep values constant. For the first few days AndroidAPS ran in the “Open Loop” mode. That is, the app is only therapy recommendations, users must do it independently. This is to make sure that you are familiar with the app before you entrust your health.
The user interface of AndroidAPS is not nice, but functional. In the main view, the app displays important data such as the blood sugar history or the amount of insulin delivered graphically and as text. It is always clear what the system is doing – ie what percentage of the delivered insulin amount has been changed and for how long. Manual interventions such as bolus delivery at meal times or the entry of a temporary blood glucose target while exercising are quick. After a few days with AndroidAPS I now spend almost every night with blood glucose levels in the target area. On calm nights, the basal rate runs through with few adjustments, on some nights the system regulates it properly and successfully. My blood sugar spikes after exercise now much more harmless and require less manual intervention. In addition to better values, the new feeling of higher security is also an important aspect. Regular checks and attention when using AndroidAPS are still required. Although the glucose sensors are usually very accurate, in case of doubt you measure manually.
Should the system fail, the basal rate continues to run. Like most diabetics, I have enough alternative and replacement options, such as a conventional blood glucose meter, insulin disposable syringes and glucose.
What is diabetes type 1?
Type 1 diabetes is an autoimmune disease in which the immune system destroys the insulin-producing beta cells in the pancreas. Patients therefore need to subcutaneously administer insulin to their body for a lifetime to keep their blood sugar under control. Over- or under-sugar can be felt differently. Acute, they range from tiredness to unconsciousness. If they persist, they can cause damage to the eyes, kidneys or heart, for example. How much insulin the more than 300,000 patients have to inject is individually different, depends on many factors and varies from day to day and night to night. Planning, calculating, making decisions about the right dose of insulin, treating excessively high and too low blood sugar levels – the illness is a 24-hour job.
And what is the industry doing?
Unlike the developers of the DIY movement, the pharmaceutical industry has some additional hurdles to overcome. They have to meet strict licensing requirements and often complete multi-year authorization procedures. In addition, commercial solutions must be able to be used by all patients, not just those with a technical background.
The French company Diabeloop wants to use artificial intelligence to automate the meal-dependent insulin needs – so far a weakness of closed-loop systems. The algorithm should gradually remember the diet and exercise habits of the user and include them in the calculations.
Pharmaceutical companies such as Medtronic, Ypsomed and Medtrum are also working on solutions. Among other things, Medtronic offers a simple closed-loop system in the USA with the Minimed 670g. From Sooil there is the first freely available insulin pump Dana Diabecare RS, which is controlled by smartphone and communicates with AndroidAPS. It costs 3700 euros.
The non-profit organization Tidepool developed on the basis of the iOS app Loop a solution that is regularly obtained from the AppStore. Tidepool Loop will initially support the soon to be available insulin pump Omnipod Dash, more pumps will follow.