Using an artificial pancreas (closed-loop control system) could make it easier for adolescents with Type 1 diabetes to participate in intensive outdoor physical activities, according to a study published in Diabetes Care. 

The study, which had participants ski or snowboard for five days, found that subjects who used an artificial pancreas maintained a healthy blood sugar level more of the time than participants that used the traditional open-loop system. Researchers from the University of Virgina used their own CLC system, call the Diabetes Assistant (DiAs) in the study, which uses an algorithm, pump, and insulin delivery system. The participants' CGM system was linked into the DiAs system. In the treatment group, DiAs was connected to a pump and controlled all insulin delivery. 

Intense exercise is often a struggle for people living with Type 1 diabetes. 
 
“Glucose control during exercise, especially during intense exercise, is a particular challenge for people with Type 1 diabetes,” authors of the study wrote. “Despite the well-defined benefits of physical activity (PA), exercise can still be dangerous in T1D and can result in hypo- or hyperglycemia due to fast-changing insulin sensitivity, increased energy expenditure, and possible counter-regulatory response (16). Thus, it is desirable for patients and health care providers to understand how CLC systems will work in the setting of commonly enjoyed demanding sports.”

Researchers decided to study skiing because it mixed prolonged physical activity with varied intensities and metabolic effects and is combined with cold, altitude, stress, fear, and excitement, according to the study. 

Thirty-three subjects between the ages of 10 and 16 were enrolled in the study. Participants had a range of ski experience and ablity levels. For five days, subjects participated in a ski and winter snowboarding camp either in Colorado or Virginia. Each of the days, participants completed five hours of on-snow activity and after dinner activities. All of the participants were monitored by a study team, including a study physician, 24 hours a day, according to the study. 

The experimental group used the artificial pancreas and the control group used an insulin pump, with setting adjusted for exercise and with CGM remote monitoring alerts. 

Participants that used the artificial pancreas had a healthy blood sugar range (70-180 mg/dL) 71.3 percent of the time, whereas participants that used the open loop monitor had that range 64.7 percent of the time, according to the study. 

Skiers who used the artificial pancreas were less exposed to hypoglycemia regardless of level, according to the study. The study found that skier experience was linked to hypoglycemia exposure. The chance of hypoglycemia exposer decreased from beginners to more advanced skiers.

“Hypoglycemia remains the major concern in pediatric patients with Type 1 diabetes engaging in significant exercise,” authors of the study wrote. “Results from our ski camp study show that the system limited hypoglycemia exposure overall (percent time spent below 70 mg/dL), during the day and specifically during skiing, but overnight control was highly dependent on the participant’s ski level, suggesting that more experienced skiers were more adept at managing their risk for hypoglycemia than less experienced skiers.” 

Researchers from the University of Virginia have conducted other studies that look at adolescents and the use of artificial pancreas in a camp setting. In the future studies about the use of an artificial pancreas will need a longer duration and less supervision.

The first closed loop system was cleared by the FDA in September 2016. Medtronic's MiniMed 670G, the first system to be cleared, still requires patients to manually dose insulin to conunteract meals.