Introduction aux APS et à AAPS
Qu’est ce qu’un « Système de Pancréas Artificiel” (APS)?
Un pancréas humain fait beaucoup de choses en plus de réguler la glycémie. Cependant, le terme « Système de pancréas artificiel » (APS) fait généralement référence à un système qui agit pour maintenir automatiquement les niveaux de glycémie dans les limites de la santé.
La façon basique de faire cela est de détecter les niveaux de glycémies, utiliser ces valeurs pour faire des calculs, puis d’injecter le montant correct (estimé) d”insuline dans le corps. Il répète le calcul régulièrement (quelques minutes), 24h/24, 7j/7. Il utilise des alarmes et des alertes pour informer l’utilisateur si une intervention ou une attention est nécessaire. Ce système est généralement composé d’un **capteur de glycémie **, d’une pompe à insuline et d’une application sur un smartphone.
Vous pouvez en savoir plus sur les différents systèmes de pancréas artificiels actuellement disponibles et en cours de développement dans cet article de synthèse de 2022 :
Future Directions in Closed-Loop Technology / Futures directions dans les technologies de boucle fermée (article en anglais).
Dans un avenir proche, certains systèmes dits de « double hormone » auront également la possibilité d’injecter du glucagon en plus de l’insuline, dans le but de prévenir les hypoglycémies sévères et de permettre un contrôle encore plus rigoureux de la glycémie.
An artificial pancreas can be thought of as an “autopilot for your diabetes”. What does that mean?
Dans un avion, un pilote automatique ne fait pas tout le travail du pilote humain, ainsi le pilote ne peut pas dormir pendant la totalité du vol. Le pilote automatique facilite le travail du pilote. Il soulage le pilote du fardeau de la surveillance permanente de l’avion, lui permettant de se concentrer de temps à autre sur une surveillance de plus haut niveau. Le pilote automatique reçoit des signaux de divers capteurs. Un ordinateur les évalue en même temps que les spécifications du pilote, puis il effectue les ajustements nécessaires, en informant le pilote de tout motif de préoccupation. Le pilote n’a plus à se soucier de prendre constamment des décisions.
Que signifie « boucle fermée hybride » ?
La meilleure solution pour le diabète de type 1 serait un « traitement fonctionnel » (probablement un implant de cellules pancréatiques protégées du système immunitaire). En attendant son arrivée, un pancréas artificiel « boucle fermée complète » serait probablement le meilleur choix. Il s’agit d’un système technologique qui n’a besoin d’aucune entrée utilisateur (comme les bolus d’insuline pour les repas, ou l’annonce d’une activité physique), avec une bonne régulation des taux de glycémie. Pour le moment, il n’existe pas de systèmes largement disponibles qui soient en boucle fermée « complète », ces systèmes ont tous besoin de quelques informations entrées par l’utilisateur. Les systèmes actuellement disponibles sont appelés boucles fermées « hybrides », car ils utilisent une combinaison de technologie automatisée et d’informations entrées par l’utilisateur.
Qu’est-ce que Android APS (AAPS) ?
Figure 1. Description succinte du système APS d’Android (Artificial Pancréas System), AAPS.
Android APS (AAPS) is a hybrid closed loop system, or Artificial Pancreas System (APS). It makes its insulin dosing calculations using established OpenAPS algorithms (a set of rules) developed by the #WeAreNotWaiting type 1 diabetes community.
Since OpenAPS is only compatible with certain older insulin pumps, AAPS (which can be used with a wider range of insulin pumps) was developed in 2016 by Milos Kozak, for a family member with type 1 diabetes. Depuis ses débuts, AAPS a été sans cesse développé et amélioré par une équipe de développeurs informatiques bénévoles et d’autres passionnés qui ont une connexion avec le monde du diabète de type 1. Aujourd’hui, AAPS est utilisé par environ 10 000 personnes dans le monde entier. C’est un système hautement personnalisable et polyvalent, et parce qu’il est open source, il est également facilement compatible avec de nombreux autres logiciels et plateformes open-source pour le diabète. The fundamental components of the current AAPS system are outlined in Figure 1 above.
Quels sont les composants de base d’AAPS ?
Le « cerveau » d’AAPS est une application que vous construisez vous-même. Des instructions détaillées sont fournies pour la construire. You then install the AAPS app on a compatible Android smartphone (1). Un certain nombre d’utilisateurs préfèrent conserver leur boucle sur un téléphone distinct de leur téléphone principal. Vous pouvez donc par exemple utiliser un téléphone Android juste pour faire fonctionner votre boucle AAPS et utiliser votre téléphone habituel pour toutes vos autres activités.
The Android smartphone will also need to have another app installed on it as well as AAPS. This is either a modified Dexcom app called build-your-own dexcom app BYODA or Xdrip+. This additional app receives glucose data from a sensor (2) by bluetooth, and then sends the data internally on the phone to the AAPS app.
L’application AAPS utilise le processus de prise de décision (algorithme) d’OpenAPS. Les débutants commencent à utiliser l’algorithme de base oref0 , mais il est possible de passer à l’utilisation de l’algorithme oref1 plus récent au fur et à mesure que vous progressez avec AAPS. Le choix de l’algorithme (oref0 ou oref1) sera à effectuer en fonction de celui qui correspondra le mieux à votre situation. Dans les deux cas, l’algorithme prend en compte plusieurs facteurs, et effectue des calculs rapides chaque fois qu’une nouvelle lecture provient du capteur de glycémie. The algorithm then sends instructions to the insulin pump (3) on how much insulin to deliver by bluetooth. All the information can be sent by mobile data or wifi to the internet (4). Ces données peuvent également être partagées avec des abonnés, si souhaité, et/ou collectées pour analyse.
Quels sont les avantages du système AAPS ?
L’algorithme OpenAPS utilisé par AAPS contrôle les glycémies en l’absence de saisie de l’utilisateur, selon les paramètres qu’il a définis (les plus importants étant les débits de basale, les facteurs de sensibilité à l’insuline, les ratios Glucides/Insuline, la durée d’activité de l’insuline, etc.) , en réagissant toutes les 5 minutes aux nouvelles données transmises par le capteur. de glycémie. Certains des avantages les plus appréciés de l’utilisation d’AAPS sont les options de réglage fin et adaptable à chaque personne, la possibilité de mise en place d’automatisations et une plus grande transparence du système pour le patient et le soignant. This can result in better control over your (or your dependant’s) diabetes, which in turn may give improved quality of life and increased peace of mind.
Specific advantages include:
1) Safety built-in
To read about the safety features of the algorithms, known as oref0 and oref1, click here. The user is in control of their own safety constraints.
1) Hardware flexibility
AAPS works with a wide range of insulin pumps and sensors. Ainsi, par exemple, si vous développez une allergie à la colle du capteur Dexcom, vous pourrez à la place, basculer vers un capteur Freestyle libre. Cela offre de la flexibilité au fur et à mesure que votre vie évolue. You don’t have to rebuild or reinstall the AAPS app, just tick a different box in the app to change your hardware. AAPS is independent of particular pump drivers and also contains a « virtual pump » so users can safely experiment before using it on themselves.
2) Highly customisable, with wide parameters
Users can easily add or remove modules or functionality, and AAPS can be used in both open and closed loop mode. Here are some examples of the possibilities with the AAPS system:
a) The ability to set a lower glucose target 30 min before eating; you can set the target as low as 72 mg/dL (4.0 mmol/L).
b) If you are insulin-resistant resulting in high blood sugars, AAPS allows you to set an automation rule to activate when BG rises above 8 mmol/L (144 mg/dL), switching to (for example) a 120% profile (resulting in an 20% increase in basal and strengthening of other factors too, compared to your normal profile setting). L’automatisation prendra fin après la durée que vous aurez vous-même programmé. Une automatisation pourrait par exemple être configurée pour être active seulement certains jours de la semaine, ou certaines heures de la journée, ou même en certains lieux.
c) Si votre enfant se retrouve sans prévenir sur un trampoline, AAPS permettra de suspendre l’injection d’insuline pour une période déterminée, directement via le téléphone.
d) After reconnecting a tubed pump which has been disconnected for swimming, AAPS will calculate the basal insulin you have missed while disconnected and deliver it carefully, according to your current BG. Any insulin not required can be overridden by just “cancelling” the missed basal.
e) AAPS has the facility for you to set different profiles for different situations and easily switch between them. For example, features which make the algorithm quicker to bring down elevated BG (like supermicro boluses (“SMB”), unannounced meals, (“UAM”) can be set to only work during the daytime, if you are worried about night-time hypos.
These are all examples, the full range of features gives huge flexibility for daily life including sport, illness, hormone cycles etc. En résumé, c’est à l’utilisateur de décider comment utiliser cette flexibilité, et il n’y a pas une automatisation unique pour tout le monde.
3) Remote monitoring
There are multiple possible monitoring channels (Sugarmate, Dexcom Follow, Xdrip+, Android Auto etc.) which are useful for parents/carers and adults in certain scenarios (sleeping/driving) who need customisable alerts. Dans certaines applications (Xdrip+), vous pouvez également désactiver complètement les alarmes ce qui est génial si vous avez un nouveau capteur « en cours d’initialisation » ou en attente avec lequel vous ne voulez pas encore boucler.
4) Remote control
A significant advantage of AAPS over commercial systems is that it is possible for followers, using authenticated text (SMS) commands or via an app (Nightscout or AAPSClient) to send a wide range of commands back to the AAPS system. Ce type de commande est largement utilisée par les parents d’enfants atteints de diabète de type 1 qui utilisent AAPS. It is very useful: for example, in the playground, if you want to pre-bolus for a snack from your own phone, and your child is busy playing. It is possible to monitor the system (e.g. Fitbit), send basic commands (e.g. Samsung Galaxy watch 4), or even run the entire AAPS system from a high-spec smartwatch (5) (e.g. LEMFO LEM14). In this last scenario, you don’t need to use a phone to run AAPS. As battery life on watches improves and technology becomes more stable, this last option is likely to become increasingly attractive.
5) No commercial constraints, due to open application interfaces
Beyond the use of an open-source approach, which allows the source code of AAPS to be viewed at any time, the general principle of providing open programming interfaces gives other developers the opportunity to contribute new ideas too. AAPS is closely integrated with Nightscout. This accelerates development and allows users to add on features to make life with diabetes even more convenient. Good examples for such integrations are NightScout, Nightscout Reporter, Xdrip+, M5 stack etc. There is ongoing dialogue between open-source developers and those developing commercial systems. Many of the DIY innovations are gradually adopted by commercial systems, where developments are understandably slower, partly because interfaces between systems from different companies (pumps, apps, sensors etc) need to be carefully negotiated and licenced. This can also slow innovations which are convenient for the patient (or a small sub-population of patients, who have a very specific requirement) but do not generate any sizable profit.
6) Detailed app interface
With AAPS it is easy to keep track of things like: pump insulin levels, cannula age, sensor age, pump battery age, insulin-on-board etc. Many actions can be done through the AAPS app (priming the pump, disconnecting the pump etc.), instead of on the pump itself, which means the pump can stay in your (or your dependant’s) pocket or belt.
7) Accessibility and affordability
AAPS gives people who currently can’t afford to self-fund, or don’t have funding/insurance, access to a world-class hybrid closed looping system which is conceptually years ahead, in terms of development, of the commercial systems. You currently need to have a Nightscout account to set up AAPS, although the Nightscout account is not required for day-to-day running of the AAPS loop. Many people continue to use Nightscout for collecting their data, and for remote control. Although AAPS itself is free, setting up Nightscout through one of the various platforms may incur a fee (€0 - €12), depending on what level of support you want (see comparison table) and whether you want to keep using Nightscout after setup or not. AAPS works with a wide range of affordable (starting from approx €150) Android phones. Different versions are available for specific locations and languages, and AAPS can also be used by people who are blind.
No automated insulin delivery system is perfect. Commercial and open-source systems share many common glitches in both communications and temporary hardware failure. There is support available from community of AAPS users on Facebook, Discord and Github who designed, developed and are currently using AAPS, all over the world. There are also Facebook support groups and help from clinic/commercial companies for the commercial APS systems - it is worth speaking to the users, or former users of these systems to get feedback on the common glitches, the quality of the education programme and the level of ongoing support provided.
9) Predictability, transparency and safety
AAPS is totally transparent, logical and predictable, which may make it easier to know when a setting is wrong, and to adjust it accordingly. You can see exactly what the system is doing, why it is doing it, and set its operational limits, which puts the control (and responsibility) in your hands. This can provide the user with confidence, and a sounder sleep.
10) Access to advanced features through development (dev) modes including full closed loop
This AAPS documentation focuses on the mainstream “master” branch of AAPS. However, research and development is going on all the time. More experienced users may wish to explore the experimental features in the development branch. This includes integration of Dexcom G7, and automatically adjusting insulin delivery according to short-term sensitivity changes (DYNISF). The development innovations focus on strategies for full closed looping (not having to bolus for meals etc.), and generally trying to make life with type 1 diabetes as convenient as possible.
11) Ability to contribute yourself to further improvements
Type 1 diabetes can be highly frustrating and isolating. Having control over your own diabetes tech, with the possibility to “pay it forward” as soon as you are making progress by helping others on their journey can be really rewarding. You can educate yourself, discover the roadblocks and look for, and even contribute, to new developments and the documentation. There will be others in the community with the same quest that you can bounce ideas off and work with. This is the essence of #WeAreNotWaiting.
AAPS utilise-t-il une intelligence artificielle ou un algorithme d’apprentissage ?
The current master version of AAPS (126.96.36.199) does not have any machine learning algorithms, multiple-parameter insulin response models, or artificial intelligence. As such, the system is open and transparent in how it works, and has the ability to be understood not just by experts, but also by clinicians and patients. It also means that if you have a sharply varying schedule (maybe switching from a stressful week at work to a relaxing holiday) and are likely to need a significantly different amount of insulin, you can immediately switch AAPS to run a weaker/stronger customised profile. A ‘learning system’ will do this adjustment for you automatically, but is likely to take longer to adjust the insulin delivery.
Which system is right for me or my dependant?
Practically, your choice of system is often restricted by which pump you already have, or can obtain from your medical provider, and your choice of phone (Apple or Android). If you don’t yet have a pump you have the biggest choice of systems. Technology is continually evolving, pumps are being discontinued and new pumps and sensors are being released. Most open-source systems work with the main sensors (Libre and Dexcom) or are quickly adapted to work with new sensors a year or so after they are released (with a bit of time delay for safety and stability testing).
Most AAPS users report more time in range, HbA1c reductions, as well as quality of life improvements from having a system that can auto-adjust basal rates overnight during sleep, and this is true for most hybrid closed loop systems. Some people have a preference for a very simple system which is not very customisable (which means you may prefer a commercial system), and others find this lack of control very frustrating (you may prefer an open-source system). If you (or your dependant) are newly diagnosed, a common route is to get used to using MDI plus a glucose sensor first, then progress to a pump which has the potential for looping, then progress to AAPS, but some people (especially small kids) may go straight to a pump.
It is important to note that the AAPS user needs to be proactive to troubleshoot and fix problems themselves, with help from the community. This is a very different mindset to that when using a commercial system. With AAPS a user has more control, but also the responsibility, and needs to be comfortable with that.
Peut-on utiliser des systèmes open-source comme AAPS en toute sécurité ?
Safety of the AAPS system
A more accurate question is probably “is it safe compared with my current insulin delivery system?” since no method of insulin delivery is without risk. There are many checks and balances in place with AAPS. A recent paper looked at the use of AAPS in a computer simulated set-up, which was an effective way to unobjectively trial how safe and effective the system is. More generally, it is estimated that over 10,000 individuals worldwide are using open-source automated-insulin delivery systems, and uptake continues to increase globally.
Any device that uses radio communications could be hacked, and this is true for a non-looping insulin pump as well. Currently, we are not aware of anyone attempting to harm individuals by hacking their diabetes-related medical equipment. However, there are multiple ways to protect against such risks:
In the pump settings, limit both the max bolus allowed and max temporary basal settings to amounts that you believe are safest. These are hard limits that we do not believe any malicious hacker could circumvent.
Set your CGM alarms enabled for both highs and lows.
Monitor your insulin delivery online. Nightscout users can set additional alarms to alert for a wide variety of conditions, including conditions that are much more likely to occur than a malicious attack. In addition to highs and lows, Nightscout can display diagnostic data useful for verifying that the pump is operating as desired, including current IOB, pump temporary basal history, pump bolus history. It can also be configured to proactively alert users to undesirable conditions, such as predicted highs and lows, low insulin reservoir, and low pump battery.
If a malicious attack was made on your insulin pump, these strategies would significantly mitigate the risk. Every potential AAPS user needs to weigh the risks associated with using AAPS, versus the risks of using a different system.
Safety considerations around improving blood glucose control too fast
A rapid reduction in HbA1c and improved blood glucose control sounds appealing. However, reducing average blood glucose levels too fast by starting any closed loop system can cause permanent damage, including to the eyes, and painful neuropathy that never goes away. This damage can be avoided simply by reducing levels more slowly. If you currently have an elevated HbA1c and are moving to AAPS (or any other closed loop system), please discuss this potential risk with your clinical team before starting, and agree a timeplan with them. More general information on how to reduce your glucose levels safely, including links to medical literature is given in the [safety section here.
Medical safety around devices, consumable supplies and other medications
Use a tested, fully functioning FDA or CE approved insulin pump and CGM for an artificial pancreas loop. Les modifications matérielles ou logicielles de ces composants peuvent entraîner un dosage incorrect de l’insuline, causant un risque significatif pour l’utilisateur. If you find or get offered broken, modified or self-made insulin pumps or CGM receivers, do not use these for creating an AAPS system.
Use original supplies such as inserters, cannulas and insulin containers approved by the manufacturer of your pump and CGM. L’utilisation de consommables non testés ou modifiés peut entraîner une imprécision du MGC et des erreurs de dosage de l’insuline. Insulin is highly dangerous when misdosed - please do not play with your life by hacking your supplies.
Do not take SGLT-2 inhibitors (gliflozins) when using AAPS as they incalculably lower blood sugar levels. Combining this effect with a system that lowers basal rates in order to increase BG is dangerous, there is more detail about this in the main safety section.
Why can’t I just download AAPS and use it straight away?
The AAPS app is not provided in Google Play - you have to build it from source code by yourself for legal reasons. AAPS is unlicensed, meaning that it does not have approval by any regulatory body authority in any country. AAPS is deemed to be carrying out a medical experiment on yourself, and is carried out at the user’s own risk.
Setting up the system requires patience, determination and the gradual development of technical knowledge. All the information and support can be found in these documents, elsewhere online, or from others who have already done it. Over 10,000 people have successfully built and are currently using AAPS worldwide.
The developers of AAPS take safety incredibly seriously, and want others to have a good experience of using AAPS. That is why it is essential that every user (or carer, if the user is a child):
builds the AAPS system themself and works through the objectives so that they have reasonably good personalised settings and understand the basics of how AAPS works by the time they “close the loop”;
backs up their system by exporting and saving important files (like keystore and settings .json file) somewhere safe, so you can setup again quickly if needed;
updates to newer master versions as and when they become available; and
gèrent et surveillent le système pour s’assurer qu’il fonctionne correctement.
What is the connectivity of the AAPS system?
Figure 3 (below) shows one example of the AAPS system for a user who do not require any followers interacting with the system. Additional open-source software and platforms which are not shown can also be integrated.
Figure 4 (below) shows the full potential of the AAPS system for a user who has followers and requires a monitor and send adjust the system remotely (like a child with type 1 diabetes). Additional open-source software and platforms which are not shown can also be integrated.
How does AAPS get continually developed and improved?
Most AAPS users use the fully tested master version of AAPS, which has been tested for bugs and problems, before being released to the community. Behind the scenes, the developers try out new improvements, and test these out in “developer” (dev) versions of AAPS with a user community who are happy to do bug updates at short notice. If the improvements work well, they are then released as a new “master” version of AAPS. Any new master release is announced on the Facebook group, so that the mainstream AAPS users can read about and update to the new master version.
Some experienced and confident AAPS users conduct experiments with emerging technologies and with dev versions of the AAPS app, which can be interesting for the less adventurous users to read about, without having to do it themselves! People tend to share these experiments on the Facebook group too.
You can read more about some of these experiments and discussion on emerging tech here:
Tim Street https://www.diabettech.com/
David Burren https://bionicwookie.com/
Who can benefit from AAPS?
✔️ type 1 diabetic
✔️ caregiver or parent of a type 1 diabetic
✔️ blind users type 1 diabetic
✔️ *clincians and healthcare professionals
The above table assumes that the user has access to both continuous gluocse monitor and insulin pump.
*All data from AAPS can be made available to healthcare professionals via data sharing platforms, including Nightscout that provides logging and real time monitoring of CGM data, insulin delivery, carbohydrate entries, predictions and settings. Nightscout records include daily and weekly reports which can aid healthcare professionals” discussions with type 1 patients with more accurate data on glycemic control and any behavioural considerations.
Accessibility for users AAPS who are partially or completely blind
Day to day AAPS use:
AAPS can be used by blind people. On Android devices, the operating system has a program called TalkBack. This allows screen orientation via voice output as part of the operating system. By using TalkBack you can operate both your smartphone and AAPS without needing to be able to see.
Building the AAPS app:
As a user you will build the AAPS app in Android Studio. Many people use Microsoft Windows for this purpose, where there is the Screenreader analogous to TalkBack. Since Android Studio is a Java application, the “Java Access Bridge” component must be enabled in the Control Panel. Otherwise, the screen reader of the PC will not speak in Android Studio.
How you do this depends on your operating system, two methods are outlined below:
In the Windows Start menu, enter “Control Panel” in the search field, open with Enter. It opens: “All Control Panel Items”.
Open the « Ease of Access Centre ».
Then open “Use computer without a display” with Enter.
Under hear text read aloud select « turn on narrator » and « turn on audio display », and click « apply »
Press Windows key and enter “Control Panel” in the search field, open with Enter. It opens: “All Control Panel Items”.
Press the letter C to get to “Center for Ease of Use”, open with Enter.
Then open “Use computer without a screen” with Enter.
There, at the bottom, you will find the checkbox “Enable Java Access Bridge”, select it.
Done, just close the window! The screen reader should work now.
What benefits can I get from AAPS?
With investment of your time, AAPS can potentially lead to:
alleviating the stress and burden of managing type 1 diabetes;
reducing the multitude of mundane decisions that arise from type 1 diabetes;
the provision of personalised and dynamic insulin dosing based on real-time data which can cut down the need for hypo treatments and reduce hyperglycemia episodes;
an increased knowledge of insulin management and confidence to better fine tune your settings;
the ability to create automatic settings (automations) that are tailored to fit in with your lifestyle;
improved sleep quality and overall reduction in the frequency of nighttime interventions;
remote monitoring and administration of insulin delivery for caregivers of type 1 diabetics; and
streamlining of all your portable diabetic equipment (continuous glucose monitor receiver and insulin controlling devices) by using an Android phone controlled by AAPS.
Ultimately, AAPS can empower individuals to better manage their diabetes, resulting in stable blood sugars and improved long term health outcomes.
Interested in how to get started with setting up AAPS? Take a look at the preparing section.