Automated insulin delivery (AID) systems, also known as closed loops, are changing the way we manage type 1 diabetes. These systems, which unite an insulin pump with a continuous glucose monitor (CGM), automatically select how much insulin you need, continually adjusting dosing throughout the day, based on how high or low your blood glucose gets.
Some experts believe that almost everybody with type 1 diabetes should be using an AID system — and that they should all start as soon as they can. But despite the benefits, only a minority of people with T1D currently use AID systems, prompting questions about why this technology isn’t more widely prescribed.
Here’s a closer look at the pros and cons of AID systems and why many clinicians still aren’t prescribing the technology regularly to people with T1D.
What are AID Insulin Pumps?
Insulin pumps attach to a user’s abdomen and continually administer tiny amounts of insulin. Traditional insulin pumps offer an enhanced opportunity to design complex and sensitive insulin dosing strategies, and have helped many people improve their diabetes management. But the user still had to do most of the work — programming basal rates and carbohydrate ratios, dosing carefully for meals, reducing insulin around exercise, and keeping a close eye on blood sugar levels every step of the way.
AID systems are designed to make most of those adjustments for you. They anticipate, adjust, and correct insulin delivery based on real-time glucose measurements delivered from a CGM to the insulin pump’s app. The CGM data works with the pump’s algorithm to constantly manage the user’s insulin doses.
These systems can significantly reduce the guesswork and hour-by-hour burden involved in diabetes management, leading to improved blood glucose and A1C levels for many users.
“These systems can be life-changing for people with type 1 diabetes, but there’s a huge learning curve for the first month or two,” explains James Thrasher, MD, founder of an endocrinology clinic in Little Rock, AR.
“The first thing you need to understand is that these pumps are not completely closed-loop,” adds Thrasher. The term “closed-loop” suggests the pump can do everything for you, but users still need to order some dosing adjustments, typically for meals or exercise. Relative to a manual pump or daily injections, however, it can require significantly less work than the managing insulin usually does.
Thrasher stresses that every AID system also works a bit differently. The algorithm in Medtronic’s 780G, for example, may work better for one person than the Omnipod 5, and vice versa for someone else.
“The hardest thing to do is trust the system,” adds Thrasher. “You’re asking people with type 1 diabetes to let go of the control they have been so used to over the years, of having to manage diabetes themselves. Giving up that control and letting a system do it for you is something that’s new and it can be frightening.”
Are AID Systems Appropriate for Those Newly Diagnosed?
Some endocrinologists believe that people need more time to learn the basics of T1D and insulin, using pens or syringes, before progressing to an AID system.
“I had this patient who was diagnosed with type 1 who started using the Omnipod 5 within three weeks of their diagnosis,” says Sherri Hall, CDCES, a certified pump trainer who works with several pump manufacturers. “I was absolutely shocked. I was like, ‘who is your doctor because that is amazing!’”
In her experience, different clinics vastly differ in how quickly they prescribe newer technology like AID systems.
“I’ve worked in a practice where you get put in the pipeline as soon as you’re diagnosed to see a diabetes educator within a month, which is critical to first learn how insulin works,” says Hall. “And then they progress to learning about CGMs and pumps very quickly. Having a good system in place makes a big difference in helping people learn about their options.”
Hall also says some people are simply more ready than others for the complexities of diabetes education and the technology that comes with it.
“Some people are just ready from the moment they are diagnosed to start using a CGM and get on a pump and do what they need to do,” says Hall. “I would say a highly motivated person who wants to learn an AID system is going to learn how to do anything. If you see they have that level of medical literacy, they have support at home, they’re able to troubleshoot and know how to ask for assistance, that’s someone who could definitely get started early on this technology.”
She also sees a pattern of reluctance in established endocrinology clinics where the physicians are used to traditional methods of diabetes management and hesitant to prescribe anything new.
“That includes Mannkind’s inhaled insulin, the implantable CGM from Eversense, and the iLet pump from Beta Bionics,” says Hall, pointing to three examples — a type of insulin, a CGM, and an AID pump that all work remarkably differently than their competitors.
Despite the benefits of an AID system, Hall points out that a pump is not a low-risk device due to the many technical issues that could arise — like kinked cannulas, failed infusion sites, and the risk of diabetic ketoacidosis (DKA) if insulin isn’t being delivered properly.
She points again to the learning curve.
“Once they’re on it and they learn how to troubleshoot when things go wrong,” explains Hall, “the results are mostly really good. That’s the biggest hurdle: getting through the initial education.”
Pros and Cons of AID technology
No method of delivering insulin is perfect. AID systems come with their share of benefits and flaws, and not everyone enjoys using the tech. A few of the most significant pros and cons include the following.
Pros of AID technology
- Fewer low blood sugars: AID systems aim to reduce your risk of low blood sugar (hypoglycemia) by suspending insulin delivery when the data (blood sugar levels vs. insulin-on-board) suggests your blood sugar is going to drop below your target range. This can also lead to better quality sleep and safer sleep.
- Fewer high blood sugars: AID systems anticipate rising blood sugar levels, too. While users must still announce meals, the system will automatically adjust insulin doses to prevent or correct high blood sugars.
- Less math: An AID system does most of the insulin dosing math for you, but most systems still require you to count the carbohydrates on your plate, or at least estimate the size of your meal. After the meal, the system can also compensate for any miscalculations or other food-related challenges, like a slow-digesting high-fat meal.
- Improved time-in-range and A1C: Time-in-range studies show that users of systems like Medtronic’s MiniMed 780G achieve, on average, 80 percent time in their target blood sugar range. While the same results are certainly possible with manual insulin pumps or multiple daily injections, it may require more effort and diabetes management experience. By increasing your time-in-range, AID systems can inevitably help lower your A1C.
Cons of AID technology
- Cost: This technology is significantly more expensive than injections. The pump itself and ongoing supplies can add up to thousands of dollars per year. Adequate health insurance coverage is a critical piece of using an AID system for most people.
- Learning curve: While AID technology does take a lot of the brainwork out of managing insulin, the user still needs to understand how the algorithm technology works and be comfortable manipulating a complex device.
- Less control over dosing: Trusting an AID system means giving up some control. AID systems necessarily restrict the user’s options — for example, you may wish to set a lower target blood glucose level than the system will allow.
- Technology failures: Like any technology, insulin pumps and CGMs aren’t perfect. If your CGM measurements aren’t accurate, your pump will give you the wrong doses of insulin, surprising users with high or low blood sugar levels. If the pump’s cannula is kinked, you aren’t getting the insulin you need — which can even lead to DKA.
Clinicians Need More Training
Despite the many benefits, Thrasher says many healthcare providers only rare prescribe AID systems to patients.
“With the benefits of this technology, you would think close to one hundred percent of people with type 1 diabetes would be using it, but one of the problems is the doctor,” says Thrasher. He feels each AID system should offer educational seminars specifically intended to train physicians on this technology.
“If you’re not trained on how to use these systems, you’ll be very reluctant to suggest it to your patients, and these companies really don’t have an efficient way of educating clinicians.”
“Endocrinologists are not pump trainers,” says Hall, “so they don’t have that hands-on knowledge that diabetes pump trainers have.”
Some clinicians also worry about their ability to intervene and adjust based on patient data.
“These systems give providers less control, and fewer levers to pull, as they often say,” says Hall.
Tandem’s tSlim and Omnipod 5 offer the most adjustable settings for doctors to help refine how the systems dose insulin. Medtronic offers fewer “levers”, and the iLet offers none at all.
This means it isn’t just the person with T1D who needs to feel comfortable giving up control, Thrasher says, but also their provider.
The Takeaway
- Automated insulin delivery systems allow people with type 1 diabetes to improve their blood sugar control while reducing the number of stressful decisions they have to make.
- Doctors and endocrinologists are not always comfortable recommending these systems; if you want one, you may need to advocate for yourself.
- AID systems aren’t right for everyone, and they require a learning curve, but everyone with type 1 diabetes should be aware of them as an option.