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Artificial pancreas improves adolescents’ HbA1c, glycemic control while skiing

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October 10, 2017


A closed-loop artificial pancreas system increased glycemic control and reduced hypoglycemia in adolescents with type 1 diabetes as they played winter sports, study data show.

“The highest mean HbA1c occurs during adolescence and young adulthood, indicating that this age group is a prime target for improved glycemic control,” Marc D. Breton, PhD, assistant professor of research at the Center for Diabetes Technology at the University of Virginia School of Medicine, and colleagues wrote. “As such, closed-loop control technology, commonly known as the artificial pancreas, has become a focus of significant research and industrial development effort. … Glucose control, especially during intense exercise, is a particular challenge for people with [type 1 diabetes].”

The researchers performed a randomized controlled trial of 32 adolescents with type 1 diabetes who attended 5-day skiing camps in Breckenridge, Colorado, and Wintergreen, Virginia. The patients were randomly assigned to a University of Virginia-designed closed-loop control system or a remotely monitored sensor-augmented pump. Participants were “coarsely” matched by HbA1c and age, and the researchers monitored them remotely for 24 hours a day. The patients’ mean age was 13.2 years.

Patients assigned to the closed-loop control system demonstrated a greater percentage of time in range compared with the physician-monitored open-loop group (71.3% vs. 64.7%; P = .005), Breton and colleagues reported.

Overall hypoglycemia exposure (P = .001) and carbohydrate treatments (P = .007) were reduced, the researchers wrote. This held true during the daytime, with a significant effect in the participants’ levels of ability in skiing or snowboarding (P = .0001 and P = .006). However, those in the closed-loop control system group were exposed to hypoglycemia less than the remotely monitored group while skiing or snowboarding, regardless of ability (1.4% vs. 2.3% for beginners, 1.3% vs 2.3% for advanced) and received fewer carbohydrates (15.63 g vs. 18.53 g for beginners, 12.38 g vs. 16.03 g for advanced).

“Future studies of [closed-loop control systems] require longer duration, less supervision and challenges with activities in which patients engage in their lives,” Breton and colleagues wrote. – by Andy Polhamus

Disclosures: Breton reports receiving fees from Ascencia, Dexcom, The Epsilon Group, Merck, Roche and Sanofi; nonfinancial support from Novo Nordisk, Tandem and TypeZero Technologies; and patents relating to glucose monitoring.

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Laura Jacobsen

The goal of this study was to assess the safety and efficacy of an artificial pancreas system (termed closed-loop control) in adolescents who are not simply “exercising” but undergoing prolonged and intense exercise at skiing camp. The study randomly assigned 32 experienced insulin pump users to either University of Virginia’s closed-loop control system (treatment) or remotely monitored sensor-augmented pump (control). A positive primary outcome of increased percent time in range (70-180 mg/dL) was seen in the closed-loop control group during both the day and nighttime. During skiing and overall, the treatment group had less percent time less than 70 mg/dL. Less insulin was used during the day and while skiing. Percent time greater than 250 mg/dL was reduced in the treatment group. Beginning skiers benefited the most from closed-loop control while advanced skiers on closed-loop control demonstrated greater glycemic variation compared to those using sensor-augmented pump. Advanced athletes may have improved hypoglycemia prevention skills, but without the aid of closed-loop algorithms, they may have overall looser control during training. 

This is a relevant study to providers as more hybrid and other closed-loop systems come to market. This device demonstrated safety in intense activity in adolescents, but there are several facts to keep in mind:

  • Twenty-four-hour physician monitoring for safety provided during this study, as noted by the authors, may decrease the generalizability of these results.
  • Considerable carbohydrate intake was still required during exercise by both groups (about 50 g).
  • Close glucose monitoring during exercise remains essential.
  • Advanced athletes may have unique issues wearing artificial pancreas systems.

Given the increasing number of published studies utilizing closed-loop control systems, the potential benefit of these devices has been firmly established. However, we cannot be remiss in emphasizing the critical nature of training (and re-training) of our patients in proper exercise and diabetes management.

Laura Jacobsen, MD

Pediatric Endocrinology Fellow

University of Florida Health Shands Children's Hospital

Disclosure: Jacobsen reports no relevant financial disclosures.