International Consensus Statement on “DIY” or “Homemade” Artificial Pancreases 

Artificial pancreases, as they are commonly called, automatically administer part of the insulin that the user needs. These systems include an insulin pump, a continuous glucose monitoring (CGM) device and an algorithm that automatically adjusts insulin delivery based on blood sugar levels. 

However, the term “artificial pancreas” can be misleading. Not only do these systems require input from the user (e.g., entering the number of carbs in a meal when eating), but they also do not replicate all the functions of the pancreas—although they do perform the most important one: administering insulin to regulate blood sugar levels. This is why they are more accurately called hybrid closed-loop insulin delivery systems.

There are two types of closed-loop systems: 

• Hybrid “commercial” systems: These systems are commercially manufactured, and must be tested and then approved by Health Canada before they are made available on the market (e.g., Tandem Control-IQ, Medtronic 670/770G).
• “Non-commercial” systems, also called “DIY” or “homemade” systems: The consensus statement mentions that these terms can seem pejorative. These systems are developed by patients with type 1 diabetes (T1D) or family members with the help of open-access software (e.g., OpenAPS, AndroidAPS, Loop, FreeAPS). Since they are not approved by Health Canada, there is no training or customer service available, and healthcare professionals are not always able to give any advice on their use.

A group of experts recently published a consensus on non-commercial systems. This consensus statement lists available devices, explains how these systems can be used as a safe and effective treatment option by people with T1D, and provides recommendations to healthcare professionals.

More flexibility

The consensus also compares some technical aspects in both commercial and non-commercial systems: 

• Pump and CGM

In current commercial systems, insulin pumps can be paired only with a specific CGM device (e.g., Medtronic 770G works only with the Medtronic Enlite/Guardian sensor, and Tandem Control-IQ works only with the Dexcom G6 sensor). Non-commercial systems allow for greater flexibility in the choice of pump and CGM system.

• Algorithm 

Commercial systems are ready-to-go, in that they include some default settings that cannot be changed (e.g., the target blood sugar level for the automatic adjustment of the basal rate) to facilitate their use.

In contrast, non-commercial systems include many customizable settings that make it easier to adapt insulin delivery to the user’s needs or new types of insulin (e.g., with a shorter duration of action). These systems are more custom-made.

On the one hand, non-commercial systems offer greater flexibility to meet particular needs (e.g., pregnancy, active lifestyle, young children) that commercial systems cannot always fulfill. On the other hand, commercial systems are subject to a thorough approval process, which is not the case for non-commercial systems.

Safe, but complex

The consensus also states that open-access software is safe and optimized to improve blood sugar management by reducing hyperglycemic episodes without increasing the risk of hypoglycemia. Few studies have been conducted on non-commercial systems, but real-world experiences show that they work well.

In the absence of a training program or customer service, users turn to software developers as well as online communities (which help to identify problems and quickly fix them). Patients who want to start using non-commercial systems often learn with an existing user.

However, the flexibility that these systems offer can sometimes make them more difficult to use, and healthcare professionals are rarely in a position to help. Not only are they not trained to use these systems, but there are also legal implications because these systems have not been approved by Health Canada. 

Based on the many benefits that non-commercial systems provide, the consensus still considers that healthcare professionals should consider discussing them with patients who could benefit from using them, despite the potential legal implications.

Recommendations for better support

Since non-commercial systems are considered safe and effective, the consensus highlights the need for healthcare professionals to be able to adequately support patients who use them or wish to use them. 

Here are a few recommendations:

• Checking the prerequisites. Ensuring that patients who wish to start using a non-commercial system make an informed choice. The patient should have previous experience using an insulin pump and a CGM system.
• Supporting the initiation process. Ensuring that the patient understands the system’s features well and helping to adjust the insulin pump’s settings. There are also many resources online to help with learning how to use the system. 

Tips on using non-commercial systems

In addition to their recommendations to healthcare professionals, the experts also offer advice on how to get the best out of these systems.

Here are some examples:

• Carb consumption: Any carbs consumed (including those consumed to treat hypoglycemia) should always be entered into the system.
• Blood sugar targets: The customizable blood sugar target should be set at 6.0–6.5 mmol/L as a starting point to avoid hypoglycemia. This can be changed later.
• Hypoglycemia management: Users might consider treating hypoglycemia with fewer carbs than usual if the system has suspended insulin delivery for an extended period of time.
• Duration of insulin action: Non-commercial systems generally use a duration of insulin action of five to seven hours for rapid-acting insulin, while most commercial systems use a duration of two to five hours for rapid-acting insulin. Generally, users start with a duration of five hours and adjust this value later.
• Insulin bolus timing: As with conventional management, it is important to bolus ahead of the meal. Late boluses can cause the system to increase basal delivery, which can cause hypoglycemia.

Other strategies are discussed with regard to blood sugar management on sick days, physical activity, pregnancy, low-carb diets, etc. Among these, managing and preventing hypoglycemia brought on by physical activity seems to be the factor that still requires many adjustments and needs to be anticipated by users.

The consensus offers an opportunity for healthcare professionals to familiarize themselves with the systems, the components and the associated terminology, and to learn about certain clinical recommendations in order to help people with T1D who use or want to use these systems.

Non-commercial systems are often more complex to use than commercial systems. They also require a greater involvement in diabetes management. Patients who wish to use these systems should be able to discuss it openly with their healthcare team, and healthcare teams should respect their patients’ autonomy and choices. It is worth mentioning that data sharing could be an issue, since the clinical team would then need to learn how to use different software.