Ensuring the Right Nighttime Insulin Flow

Diabetes patients regulated nighttime blood sugar levels with an insulin pump and wireless computer

(RxWiki News) Seizures triggered by severely low blood sugar levels tend to occur when diabetes patients are asleep. Figuring out how to better regulate those blood sugar levels during sleeping hours has been an important aspect of diabetes care.

In a new study, a wireless computer programmed to detect low blood sugar and temporarily stop an insulin pump allowed type 1 diabetes patients to normalize those blood sugar levels while they slept.

Blood sugar levels that are too low can cause patients to blackout, have seizures, or in rare cases, die.

"Ask your doctor about ways to control blood sugar while sleeping."

Bruce Buckingham, MD, a pediatric endocrinologist at Lucile Packard Children's Hospital in Stanford, CA and professor at Stanford University School of Medicine, was this study’s lead author.

Dr. Buckingham and his team of investigators from the United States and Canada explored the effects of placing a glucose (blood sugar) monitor under the skin of 45 diabetes patients, aged 15 to 45, then linking that monitor to a wireless computer specially programmed to measure blood sugar levels and pump insulin as needed.

Of the 42 patients, 47 percent were males and 93 percent were white. Each patient had been taking insulin for at least a year and using an insulin pump for at least six months.

For 21 nights, as they remained asleep in their own homes, each patient used the special computer, which was near their bedside and shut off the insulin pump when blood sugar levels fell too low. When those blood sugar levels began to rise again, the computer triggered the pump to turn on.

For 21 additional nights that were randomly selected, the patients did not use the special computer that shuts an insulin pump on or off.

Study participants did not know when the computer was and was not programmed to do that monitoring.

Based on their findings, these researchers concluded that the amount of time when patients’ blood sugar levels were too low decreased by 81 percent when the special computer monitored insulin and shut the pump on and off.

These computers shut off patients’ insulin pumps at least once during 76 percent of the treatment nights. Periods when blood sugar levels remained too low for two hours or longer fell by 74 percent.

Each morning after nights of being treated with the computer-programmed insulin pump, blood sugar levels were slightly higher than on nights without the computer-programmed pump. Still, those slightly higher levels were safe, the researchers wrote.

Also each morning, patients checked their urine and blood for ketones, a substance created when the body’s blood sugars are at abnormal levels. Ketone levels were similar on mornings after being treated with the computer-programmed insulin pump control and on mornings after not receiving that treatment.

"A system like this should dramatically decrease diabetics' risk of having a seizure overnight," Dr. Buckingham said in an announcement about the study. "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."

While people with type 1 diabetes tend to readily detect low blood sugar levels during their waking hours, keeping tabs on those levels is harder while sleeping, the researchers wrote. Seventy-five percent of diabetic seizures occur at night, they added.

Insulin pumps shoot a low dose of insulin through a catheter inserted under the skin throughout the sleeping period. Previous medical trials also have involved special glucose sensors that sound an alarm when blood sugar levels drop dangerously low. However, patients in those trials slept through about 70 percent of those alarms, Dr. Buckingham and colleagues wrote.

Low blood sugar levels can cause seizures. Deaths are rare, but they also are a risk when blood sugar levels fall too low.

Dr. Buckingham and team said they now are planning to expand their study to include children aged 3 to 15 whose parents often must get up during their night to monitor their children's blood sugar levels.

"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,” Dr. Buckingham said.

This study was published online May 7 in Diabetes Care.

The National Institute of Diabetes and Digestive and Kidney Diseases, the Juvenile Diabetes Research Foundation and that foundation's Canadian Clinical Trial Network funded this study.

For this study, the pharmaceutical companies Medtronic MiniMed, LifeScan and Abbott Diabetes Care sold glucose monitors, glucose sensors, ketone meters and test strips to these researchers at a discounted price.

These researchers reported that some among them had patents pending for the special computer algorithm used in this study, and that they’ve received research grants and speaker fees from Medtronic MiniMed and Lifescan Inc. Two of the 15 researchers also sat on a pharmaceutical company board of directors or advisory board.

Review Date: 
May 6, 2014