An under-the-skin sensor connected wirelessly to a bedside computer could prevent dangerously low blood sugar in people with diabetes.
Parents of children with type 1 diabetes may soon be able to sleep more soundly, thanks to new research aimed at predicting and preventing dangerously low blood sugar levels at night.
The system, described in the May issue of Diabetes Care, involves a glucose sensor worn under the skin and an insulin pump connected to a computer near the bed. The pump delivers insulin through a catheter inserted under the skin.
The heart of the system is a specially designed computer algorithm that carefully monitors blood glucose levels, looking for signs of a possible drop. If it detects one, it responds by shutting off the delivery of insulin until levels start to rise again.
“A system like this should dramatically decrease diabetics’ risk of having a seizure overnight,” said Dr. Bruce Buckingham, professor of pediatric endocrinology at Stanford, who led the trial and is a co-author of the study, in a press release. “Patients and parents will be able to have a better night’s sleep, knowing that there is a much lower risk of severe hypoglycemia at night.”
During the day, people with type 1 diabetes usually notice the warning signs of low blood sugar and can reduce the delivery of insulin accordingly. However, these signs can be missed while they are asleep. Seventy-five percent of diabetic seizures—caused by severe low blood sugar, or hypoglycemia—occur at night. Nighttime hypoglycemia may also be the cause of 6 percent of deaths in people with diabetes who are younger than 40.
Previous attempts at alerting diabetics while they slept included glucose sensors that triggered an alarm when levels dropped too low. However, people often slept through the alarms. Because the new system is fully automated, it works while people are asleep.
The system was tested on 45 people, between the ages of 15 and 45, with type 1 diabetes. Researchers monitored each person for 42 nights. For some people, the computer based insulin delivery on the algorithm; the other group received a steadier stream of insulin through the night (this is how insulin is typically delivered to people with diabetes when they are asleep).
On treatment nights, the algorithm looked for signs that blood sugar levels would drop below 80 milligrams per deciliter within the next 30 minutes, slightly above the 70 milligrams per deciliter level that many guidelines deem low blood sugar or hypoglycemia.
With the algorithm controlling the delivery of insulin, people spent 81 percent less time with low blood glucose while they slept. In addition, the new method reduced the time spent in low blood glucose episodes by 74 percent.
People also experienced small overall increases in blood glucose levels, although this still fell within a safe range. To confirm that this wasn’t an issue, the researchers analyzed the patient’s ketone levels—a measure of high glucose levels in the blood—and found that they were similar to the levels of people in the control group.
According to the American Diabetes Association, about 1 in every 400 children and adolescents has diabetes. Parents who help children monitor their blood glucose levels must walk a fine line between levels that are too high—which can increase the risk of complications such as diabetic coma—and levels that are too low.
“A lot of parents whose children have diabetes are getting up night after night at midnight and 3 a.m. to check their children’s blood sugar levels,” said Buckingham. “We think this type of system is going to make it much easier for them to feel comfortable about letting their child with diabetes sleep through the night with fewer overnight sugar tests. Parents will be able to get a better night’s sleep, too.”
The researchers are planning on expanding their trials to a larger age group, including children between the ages of three and 15.