Bruce Buckingham MD, Professor of Pediatrics (Endocrinology) at the Lucile Salter Packard Children’s Hospital in California, talks about a new closed-loop insulin delivery system for patients with Type 1 diabetes.
Interview conducted by Ivanhoe Broadcast News in April 2017.
I’m told that you do not like the name artificial pancreas.
Dr. Buckingham: Well it’s not accurate, it implies more than what we’re doing.
So let’s talk about the hybrid closed loop insulin delivery system and can you give us an overview of how this works for people with diabetes?
Dr. Buckingham: People with Type 1 diabetes do not make adequate insulin and therefore their blood sugars go up. And to treat Type 1 you need to take insulin by injection or by a pump. Insulin is a very potent drug, it has a fairly low therapeutic margin in. If you give too much you can have lows, and if you give too little you have high blood glucose values. The high values over time can cause long-term complications from diabetes, eye or kidney problems, even amputations. The low blood sugars are an acute immediate problem and for the pediatric age group seventy five percent of seizures occur at night. It’s when people are sleeping, they aren’t awake, they aren’t aware and their blood sugar can drop to the point where a seizure occurs. So it’s scary.
Can you go back to the problems at night for Type 1 diabetics?
Dr. Buckingham: At night you’re sleeping and you aren’t able to monitor and check your blood sugars and if you’ve had extra activity during the day or taken too much insulin for a late meal, this can result in a low blood sugar over night. This can cause a seizure, and seventy five percent of seizures in pediatrics occur at night. It’s something that makes parents very anxious, so with younger children the parents are often are up testing at midnight and at three in the morning. You end up zombie parents by the morning. If a parent has ever witnessed their child having a seizure, it’s a scary event. About ten or twelve years ago, continuous glucose sensors became available. They go under the skin and they measure glucose every five minutes. Initially, they weren’t as accurate as they are today, but over the last few years they’ve become increasingly accurate. So we have been working for a number of years to take that glucose information from the sensor and allow it to control the deliver of insulin by a pump based on the sensor glucose levels. That is what a hybrid closing system is, it’s looking at the glucose reading every five minutes and then determining how much insulin should be delivered. It assesses the glucose, the rate of change of the glucose, how much insulin they’ve taken previously so the system does not overdosing the insulin. It works very, very well over night when you don’t have meals and acute events such as exercise. It works very well in controlling what we call basal insulin delivery.
It’s a wireless system that literally tells your pump that you’re down?
Dr. Buckingham: The sensor is under the skin and has a transmitter, where it transmits the glucose information to the pump. The pump has the algorithm on it to determine how much insulin needs to be delivered and then the pump has an infusion set that goes under the skin and delivers the insulin.
How big a deal is this for Type 1 diabetics?
Dr. Buckingham: I think this is a historic event. It’s something we’ve been looking for, for a long period of time. What it does is take a lot of the night time worry out of diabetes. It allows parents and people with diabetes to sleep well at night, knowing that they’re going to have pretty good glucose control over night, they’re going to be protected from severe events such as seizures, and they will wake up in the morning with a good glucose value. It targets 120 and we generally see kids waking up in the 100 to 150 range.
Sara, Jamie’s mom said it’s been like having a newborn for ten years. Have you heard that before?
Dr. Buckingham: Oh yes. You’re on a three hour schedule, so you’re checking before they go to bed, midnight, three a.m. six a.m. when they get up in the morning, like feeding a newborn. And one of the things that happens once you get up at night, say the glucose was running a little bit high and you gave a little bit of extra insulin to bring it down, then you go back to bed and you worry if you gave too much or did not give enough. You stay up for a while and then eventually you go back in and check again to see their blood glucose is doing. If someone has a low blood sugar, you will treat it , and then you need to wait at least fifteen minutes to recheck and make sure that the blood sugar is up. An event with anything happening, either a high or low glucose, can keep you up for hours a lot of time. It’s a daunting task for parents.
So this is a big deal medically for children but also for families in general?
Dr. Buckingham: Absolutely, or in adults. A lot of adults with Type 1 diabetes have significant others that have to worry about them at night, so I think this can really help decrease that burden.
Sara did say the good thing is Jamie sleeps through anything now. She’s gotten injections, she’s getting things poked and prodded all night long. So there’s a positive outcome. You said this is FDA approved and it’s going to be on the market soon?
Dr. Buckingham: Yes.
Will people be clamoring to get this or do you think people will be hesitant to rely on a system like this?
Dr. Buckingham: There are a lot of people that are, looking forward to this. I think they have a significant waiting list of people trying to get it. There are always people who are a little leery of the first generation of anything that comes out. Whether it’s the first iPhone or the first new device that’s available, and want to wait until the second or third generation comes out. There’s always that personality of, “I don’t want to be the first” and then there are other people who want to be the first and get it as soon as it’s available.
Is there anything else about offering this to patients?
Dr. Buckingham: I really think one of the important things is that their expectations about what this can do are realistic. It is really great overnight, it modulates the basal insulin. It does not give insulin for food, it does not give a correction dose without you doing a finger stick and then entering that value in. So actually the work during the day is the same or even more because there sometimes extra alarms on the sensor to make sure the sensor is functioning well.
That is the reason I read that you do not like it to be called artificial pancreas. Because it doesn’t do the work during the day, it’s when you’re prone and resting and that’s when it does its best work?
Dr. Buckingham: Yes, this is the first generation, the first commercially available device and I really think it’s amazing. The work that has been put into it by Medtronic to get this out in an expeditious manner with the FDA has been phenomenal, so that it will not be available to patients. It really has been a massive effort and I think it’s going to make a huge difference. But it has its limitations, you still need to do the carb counting, you still need to put in the meal boluses, you still need to do the finger sticks, to calibrate the sensor. There may be additional times you need to calibrate the sensor to make sure it’s working well. Since the sensor glucose is now determining insulin delivery because it’s used in a closed loop system, the burden of diabetes during the day is the same or even higher because there can be additional alarms with this system to keep you in closed loop. If you keep the system working in closed loop, it helps mitigate highs and it helps prevent lows during the day. So it does help glucose control during the day but it really, as I say, takes away the burden at night of doing a lot of glucose checking. It can handle the night time generally very well. But you aren’t going to be able to get this system and all of a sudden eat whatever you want without entering the amount of carbs and counting carbohydrates and doing a lot of the daily chores of diabetes that are currently a burden which we would like to decrease in the future.
This is not a silver bullet then?
Dr. Buckingham: Correct. This is the first step, it’s a historic step, it’s going to make a big difference in people’s lives and how they sleep at night. I think it’s going to really significantly decrease the incidence of seizures over night, but there’s still a lot of work in managing diabetes during the day which is the hybrid component of the system. It’s an assist during the day and it does a great job of assisting over night. But it’s an assist, it isn’t a full system. In a car analogy, you’re still driving, putting on the gas, putting on the brakes, and making the turns, but it provides power braking and steering, but it is not an auto pilot car.
The pump, did the pump not do that before?
Dr. Buckingham: Previously the insulin infusion pump delivered insulin and had a pre-programmed basal rate that you could program either to be the same all through the day, or to go up say in early morning hours when some people may have insulin resistance. It’s called the dawn phenomenon and that happens around three or four in the morning, so you can program the pump to give more insulin at that time. The problem is the dawn phenomenon doesn’t occur every night and it doesn’t occur in all people, so there is a lot of variability with the dawn phenomenon. The hybrid close-up system will adjust to whatever your blood sugar is every 5 minutes over night so with this system the basal rate is done automatically.
It reads your body as opposed to you entering the information.
Dr. Buckingham: Exactly.
END OF INTERVIEW
This information is intended for additional research purposes only. It is not to be used as a prescription or advice from Ivanhoe Broadcast News, Inc. or any medical professional interviewed. Ivanhoe Broadcast News, Inc. assumes no responsibility for the depth or accuracy of physician statements. Procedures or medicines apply to different people and medical factors; always consult your physician on medical matters.
If you would like more information, please contact:
Kate DeTrempe
KDeTrempe@stanfordchildrens.org
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