Insulin Pump Shut-Off Feature Prevents Low Blood Sugar, Study Finds

Device could improve quality of life for people with type 1 diabetes, experts say

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By Serena Gordon
HealthDay Reporter

TUESDAY, Sept. 24 (HealthDay News) -- A new type of insulin pump reduced the number of moderate to severe low-blood-sugar episodes experienced by people with type 1 diabetes.

The pump has a special sensor that can detect dropping blood-sugar levels and then suspend insulin delivery to prevent the development of dangerously low blood sugar (hypoglycemia), according to the researchers.

"Hypoglycemia is a major problem in diabetes treatment," said study senior author Dr. Timothy Jones, of Princess Margaret Hospital for Children in Perth, Australia. "The aim of the trial was to test whether a new type of insulin pump reduces life-threatening hypoglycemic events in patients with type 1 diabetes."

"We found, in a randomized trial, that this technology was able to prevent severe hypoglycemia," he said. "We don't like to be dramatic, but this may save lives, and certainly will improve quality of life and diabetes control."

The findings are published in the Sept. 25 issue of the Journal of the American Medical Association.

Type 1 diabetes is an autoimmune condition in which the body's immune system mistakenly destroys the insulin-producing cells in the pancreas. Insulin is a hormone that helps usher blood sugar into the body's cells to be used as fuel. Without insulin, blood-sugar levels rise and eventually reach life-threatening levels.

Since their bodies no longer produce insulin, people with type 1 diabetes must replace that lost insulin. To do this, they must either take multiple daily injections of insulin or use an insulin pump that has a tiny catheter inserted underneath the skin to deliver the insulin.

Getting the right amount of insulin can be difficult, however. People with diabetes have to factor in the amount of food they've eaten, their activity levels and many other factors that can affect blood sugar, and then figure out how much insulin they need.

If they get too much insulin, dangerously low blood-sugar levels can occur. Early symptoms of hypoglycemia can include shaking, sweating, confusion and a rapid heartbeat. If left untreated, hypoglycemia can cause seizures and even death, according to the American Diabetes Association. Too little insulin can cause high blood-sugar levels (hyperglycemia), which increases the risk of diabetes complications over time.

Currently, insulin pumps are completely user-driven. They do nothing automatically, other than deliver insulin. People with diabetes have to tell the pump how much insulin to deliver, or to stop insulin delivery when blood-sugar levels drop too low.

The new study looked at an insulin pump with a blood-sugar sensor and the capability to suspend insulin delivery if blood-sugar levels go too low. This device is already approved for use in Australia, where the study was conducted, Jones said. And, according to the website of the device's manufacturer, Medtronic, it also has been approved in Europe and Canada, and has been submitted to the U.S. Food and Drug Administration for approval.

The new study compared 49 people on standard pump therapy to 46 people on the low-glucose insulin suspension pump. The study volunteers were between the ages of 4 and 50, and all had type 1 diabetes.

Before the start of the study, the people in the low-glucose insulin suspension group had about six times the rate of moderate to severe hypoglycemic episodes compared to those in the standard pump therapy group.

After six months, that trend almost reversed, and people in the standard insulin pump group had nearly four times as many hypoglycemic episodes as those with the low-glucose insulin suspension pump.

The study found no difference in levels of long-term blood-sugar control between the groups, and there were no serious episodes of high blood-sugar levels in either group.

"The major findings were that moderate and severe hypoglycemia was reduced significantly on the new treatment," Jones said. "There were zero overnight convulsions in the group on the low-glucose suspend treatment, whereas the group on usual therapy continued to have events at the same rate as before."