New pump for diabetics
BACKGROUND: Close to 8% of the United States population has diabetes and out of all the people with diabetes, 5% of them have type 1 diabetes. (Source: www.diabetes.niddk.nih.gov) Usually occurring in children, adolescents, and young adults, type 1 diabetes occurs when beta cells do not produce or produce very little insulin. Insulin is a hormone created by beta cells that are located in the pancreas. Without the right amount of insulin, glucose builds up in the bloodstream instead of spreading into the cells and results in the body not being able to use this glucose for energy. The exact cause of type 1 diabetes remains unknown. Doctors believe it is an autoimmune disorder that starts as an infection that then can trigger the body to attack the beta cells. (Source: www.ncbi.nlm.nih.gov)
SYMPTOMS: Type 1 diabetes signs and symptoms can come quickly.
· When blood sugar is high, symptoms can include: being very thirty, feeling hungry, feeling fatigued, losing weight, having tingling feet, having blurry eyesight, urinating more often, stomach pain, flushed face, fruity breath odor, flushed skin, nausea, dry skin and mouth, and rapid breathing.
· Blood sugar can become low when diabetics take insulin. Symptoms usually appear when blood sugar falls below 70mg/dL, they include: hunger, weakness, sweating, headache, shaking, rapid heartbeat, nervousness. (Source: www.ncbi.nlm.nih.gov)
TREATMENT: Once the doctor analyzes the patients' blood sugar monitoring and urine testing, they will develop a diary of meals, snacks, and insulin injections that they should follow. Insulin lowers blood sugar by letting it leave the bloodstream and enter cells. All type 1 diabetes patients have to take insulin every day. Insulin is injected under the skin, but sometimes a pump can deliver the insulin all the time. Insulin injections depend on the individual person. The insulin amount has to be adjusted when they exercise, eat more or less food, travel, and when they are sick. One of the most important parts of treatment is managing blood sugar levels. Patients can check their blood sugar levels at home, usually by pricking their finger with a small needle called a lancet to get a tiny drop of blood. The blood is then placed on a strip and into the device to read. (Source: www.ncbi.nlm.nih.gov)
NEW TECHNOLOGY: A new technology, called the Veo insulin pump, is taking diabetes management to a new level. A risk of type 1 diabetes is the risk of death through low blood sugar. This pump monitors every waking and sleeping hour. It monitors and records glucose levels so the patient and doctor know exactly what is happening. It makes easy therapy adjustments and it warns when the glucose levels are off target. The pump will automatically stop insulin delivery when glucose levels are dangerously low to help reduce the chances of severe hypoglycemia. The pump is smaller than most mobile phones. It acts like a pancreas by pumping tiny amounts of insulin into the body all day. It can be clipped to a belt, kept in a pocket, or hid under the clothes. A tiny tube is connected from the pump to an even smaller tube (cannula) that sits under the skin. It can easily be disconnected and reconnected. The pump is awaiting FDA approval in the U.S., but is available in several countries. (Source: www.Medtronic-diabetes.co.uk)
Dr. Ruth S. Weinstock, MD, PhD, Endocrinologist at Upstate Medical University Joslin Diabetes Center, talks about a new insulin pump system for patients with type 1 diabetes.
How does type 1 diabetes differ from type 2 diabetes?
Dr. Weinstock: Type 1 diabetes affects approximately 10 percent of people with diabetes, but it's increasing in prevalence. Actually, it's increasing three to five percent each year. So not only is type 2 increasing, but type 1 is increasing as well. Even though the most commonly thought of age of onset is in youth; it can occur at any age. It's different from type 2 diabetes in that in most people with type 1 diabetes the ability of their own pancreas to make the hormone insulin, which is what you need to keep your blood sugars normal, has been destroyed. So you absolutely have to use insulin to control your blood glucose levels. And insulin can only be given by injections, which means people with type 1 diabetes need to take insulin at least three to four times a day by injection or be using an insulin pump. Even with testing multiple times per day; doing finger sticks, squeezing out a drop of blood multiple times a day, and using multiple injections a day or an insulin pump, it's still extremely difficult for most of our patients with type 1 diabetes to keep their blood glucose levels in an ideal range.
Are there lots of things that can affect blood sugar levels? Not just what you eat?
Dr. Weinstock: Yes. There are many factors that affect blood glucose levels. What you eat of course is one of them. Also there is your level of activity, level of stress, hormonal levels, and probably other additional factors that we don't completely understand. Some people with type 1 diabetes still make a very small amount of insulin which makes their diabetes a little easier to manage. There are many people who don't make any insulin at all, and for those people it's extremely difficult with our current tools to keep the blood glucose levels in an ideal range. What we worry about is if you give a little too much insulin, the blood sugar levels could go way too low, called hypoglycemia. That's a dangerous situation. You can lose consciousness, pass out, and have a seizure, so that's obviously an extremely dangerous situation. Having glucose levels too high over a long period of time is also not ideal. So our goal is to try to get the blood glucose levels as close to normal as possible, but without undue risk. What we're very excited about now are some new technologies that are being made available that hopefully will help people with type 1 diabetes control their blood sugar levels better. The ultimate goal is an artificial pancreas. The ultimate goal is to have a system that would automatically sense what your blood sugar or blood glucose level is and give you just the right amount of insulin to keep your blood sugars at target or goal range.
How serious are the low blood sugars? What can happen? How big of a fear is it for people?
Dr. Weinstock: It's an extremely important issue because severe hypoglycemia is dangerous. First of all, if your blood sugar goes low, your brain isn't getting enough glucose and you don't think clearly. So if you happen to be behind the wheel of a car, you can be in an accident or if you're doing something dangerous, such as if you're on a ladder, you could fall. You could, as I mentioned before, lose consciousness or have a seizure. The worst possible thing, which rarely but occasionally happens, is that you could go to sleep at night, your blood glucose level could go low and, then you don't wake up – you slip into a coma or die. Of course, that's the worst thing that could happen.
I saw that statistic this year that one in 20 type 1 diabetics will die of a low blood sugar. When you break down that number, it turns out to be about 400 people a day. That seems like a big number. How do you prevent lows? Isn't it true that the tighter control you have, the lows are just one of the side effects?
Dr. Weinstock: Not necessarily. Some people with high as well as low hemoglobin A1C levels, which is the test that we do that gives us an indication of what the average blood sugar has been over the past few months, have more low blood sugars. Everybody's diabetes is different so I don't like to generalize. Clearly, when people who have a problem with low sugar levels, we need to be more aware of that problem and change their glucose targets so that the target hemoglobin A1C level is appropriate to minimize the chance of severe hypoglycemia. The target glucose levels before meals and after meals aren't the same for every person with diabetes. We need to individualize these targets. For people who are more likely to go low and particularly for those who have had diabetes for a long time and cannot feel hypoglycemia, their body does not tell them that their glucose levels are going low, we have to change their targets to be a little higher because it's too dangerous to try to be lower than someone who has excellent hypoglycemic awareness and has a relatively new diagnosis of diabetes.
What causes hypoglycemia unawareness? Is it the inability to feel a low blood sugar?
Dr. Weinstock: There are several factors. It's true that in people who have a lot of low blood sugar levels, their body seems to adapt to that and doesn't warn them when their blood sugars are low. For those people, if you get rid of those low blood sugar reactions, help change their insulin dosing so that their glucose levels are higher, many of them do regain the awareness of hypoglycemia. That is definitely something that we try to do. There is also a group of patients, and these tend to be people who have had type 1 diabetes of long duration, who have actually lost the ability to feel their low sugar levels. Normally, if your blood sugar goes too low, the body has certain hormone reactions to that that help raise the blood sugar. Unfortunately after many years of type 1 diabetes, many people lose those hormonal responses so that the body isn't doing what it needs to do to raise the blood sugars as well. There are lots of factors involved, but it really varies from person to person. There are some people who have diabetes for many years and never have trouble with lows and others who can have a lot of trouble.
What is this new system?
Dr. Weinstock: Right now, there are commercially available insulin pumps. This is an insulin delivery system that gives tiny amounts of insulin over 24 hours a day to keep your blood sugar normal when you're not eating and allows you to give a larger amount of insulin when you eat to cover the increased needs around meals. The individual with diabetes is in control of this insulin delivery. They control the insulin pump. Most people with diabetes also check their blood sugars multiple times a day, particularly with type 1 diabetes. There is now what we call continuous glucose sensors that you can wear that sense what your glucose levels are in the fluid that bathes your tissues, called the interstitial fluid. It's not quite as accurate as a blood sugar reading, but it does correlate well and what's particularly useful about these continuous glucose sensors is that they show you the direction that your blood glucose level is going. For example, it shows you if your sugar level is rising very quickly or if it's falling very fast or is it staying the same over time? Because that's something that helps the individual with diabetes decide what to do. Let's say your blood sugar was normal and it's been staying normal for the past few hours and you're not eating, you don't need to do anything about it. If it was normal and it was falling extremely quickly, well then maybe you'd want to eat something to prevent a serious low level. If it was going up very high, maybe you need some extra insulin, so the direction is really helpful for people to make decisions. These devices also alarm for glucose levels that are too high or too low, but up until now, the glucose sensing devices and the pumps haven't been connected in that they don't talk to each other. The pumps up to now have not independently acted upon blood sugar levels. What we all really want is an artificial pancreas.. We want a a glucose monitoring device to sense what the blood sugar is every minute of the day, for that information to be automatically given to an insulin pump or insulin delivery system, which will know exactly how much insulin to infuse to keep your blood sugar normal so you never go too high or too low. That's what we call an artificial pancreas. This project is the first small little step towards that end. It's attacking the problem of low blood sugars because that's considered the most dangerous acute problem. What's particularly worrisome is when people go to sleep at night; they may not feel a low blood sugar. They may be in a deep sleep and not know about it and therefore not respond to an alarm. So what this new sensor and pump do is that if the sensor senses that your blood sugar is low and you do not respond to it, it will tell the pump to shut off the infusion of insulin for up to two hours, which will allow the blood sugars to rise back into the normal range. This is considered a significant safety feature. We're extremely excited about it. This system is commercially available in Europe now, and in clinical trials in the United States, but the FDA has not yet approved it. It's considered by the FDA an experimental system and we were very fortunate to be a site to help test it here in the United States.
What have the results from your study shown?
Dr. Weinstock: We don't have the results from the current clinical trial yet since the trial is not yet completed, but from the results that have been reported from elsewhere are extremely promising. It is before the FDA now so hopefully this is something that will become available in the not too distant future.
What have the studies that have been published on this shown?
Dr. Weinstock: So the studies that have been published so far using this system have shown that the low glucose suspend feature is generally effective. If someone doesn't respond to the low blood sugar, reading, the device suspends insulin for up to two hours and the blood sugars do rise back up into the normal range. So it's helped people with diabetes get their blood sugars back up and the blood sugars haven't gone too high to cause ketoacidosis or another problem. The data from Europe and the initial data looking at this in the United States show it's very promising. We hope that this system, this low glucose suspend system, will become available and will be the first step towards the artificial pancreas. In the future, there'll be more sophisticated systems, even better sensors and pumps that can sense the direction your blood sugar is going and make adjustments in insulin delivery in a more real-time fashion to prevent low and high glucose levels. That's the goal.
People do die of low blood sugars, what could this mean for patients?
Dr. Weinstock: We hope that this would prevent those unnecessary deaths. Obviously that's what we all want to do. We want to improve the lives of people with diabetes and ultimately have a cure. The study that we're participating in is sponsored by Medtronic, the manufacturers of this system. There are also other companies working on other systems and new technologies to form an artificial pancreas as well. So, we're really excited that this line of research will really help people with diabetes.
Eventually is it the hope that a system will do it all? That it will also sense that your blood sugar is high and give you insulin to correct it?
Dr. Weinstock: Right. That's what we hope. That's what we mean by closing the loop. You have a glucose sensor that is sensing your blood sugar every few minutes of every day. You have an accurate insulin pump that is delivering insulin and that they talk to each other and the closed loop means that the pump will know exactly how much insulin to give you so that your blood sugar will stay normal; not go too high, not go too low. That's something that's extremely exciting.
What did you hear from patients in your study who used this system?
Dr. Weinstock: One thing that I think surprised us when we were screening for this study and disturbed me honestly, is how many of our patients were having low blood sugars during the night and didn't realize it. At the beginning when we first looked for volunteers to do this, many of them were wearing a sensor for the first time. We found that they were having prolonged low blood sugars during sleep that we weren't aware of, which was frightening to them and us. To have a system that can help us first of all detect it and also correct it, is extremely exciting.
So it gives patients extra security?
Dr. Weinstock: Right. We don't have the data from our study yet .Volunteers for this study were using insulin pump therapy, but in the study get the great benefit of usinga sensor as well.. Some of them had never worn a sensor before, so that was great for them. Participants were randomized to have this low glucose suspend feature turned on or off and the two groups will be compared. We don't have those data yet for those comparisons for this study. The study is still ongoing and it's a multi-center study, involving sites across the country.
What's the end date for that?
Dr. Weinstock: Well, certainly within the next year we should have the results.
So the FDA will need that before approval?
Dr. Weinstock: The FDA will let the sponsor know if they require any additional information.. . I guess we'll have to wait and find out.
It is approved in other countries?
Dr. Weinstock: Yes. It's available in Europe. It's called the Veo Pump system.
There is other research ongoing in many diabetes centers throughout the world.
Some investigators are studying pumps that can dual infuse glucagon and insulin. So if the blood sugar goes too low, not only do you turn down or off insulin, but you can also infuse glucagon. r. There are some additional challenges because stable reconstituted glucagon isn't commercially available. Glucagon doesn't come in a vial like insulin, but there are companies working on new ways to manufacture it because they see the value.
Lots of times people will somehow come out of a low and life is fine. But they're not totally harmless right? If your blood sugar is sitting at 40 for hours, it's not doing "nothing" to you right? Even if you do wake up and treat it and you're fine?
Dr. Weinstock: Right. So we don't really know how low your blood sugar has to go and for how long to cause some damage. Probably it's different in different people. For someone who is 75 years old who has heart disease, a low blood sugar is probably more dangerous than in a young person with a normal heart. It's possible that a low blood sugar might cause the heart not to function properly. The same is true for the brain. If someone has vascular disease involving the brain, the brain could be hurt more by hypoglycemia, perhaps affecting cognitive function and even contributing to the development of dementia. The possibility of damage probably depends on both on how low and how long the low sugar episode lasts, individual variations based on age and genetics as well as other medical problems that the individual might have. I think it's very complicated. I think there's a lot we need to learn. A lot of research needs to be done, but it's very gratifying that we're making progress in a way that can help people.
Do you have any theories on why type 1 is increasing?
Dr. Weinstock: I don't know, but it's not just here, it's across the U.S., Scandinavia, and Europe. People are reporting an increase of three to five percent a year. When I was in medical school, which is a long time ago, the average age of diagnosis, type 1 was around when children hit puberty. Now we're seeing a lot more very young children and why the age of onset also seems to have fallen in age is something that we don't really understand.
It's one of those diseases that you don't know until you get it. There's nothing you can do to prevent it?
Dr. Weinstock: Not that we know of right now. There are other studies going on and that are planned to address this. There is a natural history study called Trial-Net, which is screening individuals who have relatives with type 1 diabetes, for autoimmunity; for the antibodies in the blood that are a marker that maybe the body has started to destroy its own insulin-producing cells. Theoretically, if, you still have enough insulin-producing cells that you don't have diabetes yet, you can you trick the immune system to try to stop that destruction so the diabetes never occurs. It would be wonderful, to have a vaccination someday to prevent type 1 diabetes.
There are some people who have the disease who don't have that marker right?
Dr. Weinstock: Yes, it's not 100%. Another approach for curing type 1 diabetes is to regenerate the beta insulin-producing cells. That's a whole other area of research that's very exciting.
What is the hygiene hypothesis?
Dr. Weinstock: The hygiene hypothesis proposes that children who develop type 1 diabetes may be less exposed to infections or other challenges to the immune system that can then affect the immune system so that these children are more prone to have an autoimmune response against insulin-producing beta cells. Other possible triggering events for the development of type 1 diabetes may be exposure to certain viruses, early introduction of cow's milk, or exposure to an environmental toxin.
FOR MORE INFORMATION, PLEASE CONTACT:
Ruth S. Weinstock, MD, PhD
Upstate Medical University, New York
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