As someone with type 1 diabetes, I am always eager to learn the latest treatment updates and ideas that are coming from Scientific Sessions. When the artificial pancreas project was introduced at last year’s Scientific Sessions, it used only a partially automated system to monitor blood glucose levels and deliver insulin. Based on research from this year’s Scientific Sessions, the next goal is to close the loop and make the system completely automated.
Here are highlights from three of the studies that were presented today:
Closing the Loop
One study, which is part of the JDRF Artificial Pancreas Project, has been working on a fully automated closed-loop system that uses an insulin pump and CGM. The pump has to have a sophisticated control algorithm that accounts for many different factors. Once the system is initiated, all insulin calculations and delivery are done automatically without having to inform the system that you’re eating or skipping a snack.
The researchers evaluated the system in two ways: one involved developing both a personalized model and a control algorithm based on three days of CGM, insulin pump, and meal information. The second step was to try it out in a clinical setting, where the challenge was to maintain normal blood glucose levels (which were defined as 80 to 140 mg/dl) and overcome an unplanned meal.
When the researchers tried this out, they found that on average, participants were within a range of 80-180 mg/dl 77% of the time. The system recognized the “surprise” meal and gave extra insulin appropriately. There was one mild episode of hypoglycemia, which was the result of a CGM sensor being inaccurately high and the system providing a little too much insulin to make up for the high blood glucose level.
Of course, while meals are a major factor in the struggle to control blood glucose levels, there are other factors that can send them up or down. That’s why another study looked at high blood glucose caused by stress. Of course, stress affects each person differently, so developing an algorithm to accommodate for stress can be a tricky task.
If you’re like me, stress can make your blood glucose go up. This is a hormonal reaction that makes your body less sensitive to insulin, similar to type 2 diabetes. To simulate this for the purpose of research, researchers used a hormone to induce reductions in insulin sensitivity and tested the algorithm to see if the system would adjust.
The system detected the reduced insulin sensitivity and increased the amount of insulin it gave the participant, meaning that the blood glucose was able to maintain a more normal level. This study is continuing, but I’m glad for the hope that one day I won’t have to stress about stress!
Don’t Go Too Low
Another research group looked at the possibility of an automatic insulin shut-off mechanism that could prevent severe hypoglycemia in children. This means that when the CGM senses that the blood glucose levels are getting too low, the insulin pump would stop pumping insulin. The goal is to reduce hypoglycemic episodes.
The system worked when low blood glucose was detected and shut off the insulin delivery. This happened about 2.5 times each day for each participant. Much of these incidents did not require insulin shut-off, however, as the participants realized their blood glucose was going low, and they treated it. Of the times where the insulin delivery was shut off, 42% of the cases lasted less than 30 minutes. Some cases lasted longer than 120 minutes, but that was more frequently at night. There were no episodes of high blood glucose following the insulin delivery shut-off.
Researchers believe this indicates that an automatic insulin shut-off mechanism in insulin pumps can reduce the risk for low blood glucose without compromising safety.
You can learn more about the concept of the artificial pancreas in this Diabetes Forecast article.