Children with type 1 diabetes assigned to a bihormonal bionic pancreas system for 5 days while attending a diabetes camp saw reduced plasma glucose concentrations, fewer hypoglycemic episodes and lower frequency of carbohydrate interventions than children assigned insulin pump therapy, according to research in The Lancet Diabetes & Endocrinology.
“Unlike other automated and semi-automated insulin-delivery systems, the bionic pancreas tested in this study requires only the patient's body weight for initialization and does not depend in any way upon the patient’s usual insulin regimen,” Edward Damiano, PhD, professor of biomedical engineering, Boston University, told Endocrine Today. “Once the system is initialized with body weight, it adapts automatically and continuously to the ever-changing insulin needs of the patient.”
Damiano and Steven J. Russell, MD, assistant professor of medicine at Massachusetts General Hospital and Harvard Medical School, and colleagues analyzed data from 19 children aged 6 to 11 years with type 1 diabetes for at least 1 year on insulin pump therapy, recruited from two overnight diabetes camps between July and August of 2014 (13 girls; mean age, 9.8 years; mean BMI, 17.8 kg/m²; mean diabetes duration, 5 years). Researchers randomly assigned children to 5 days of artificial pancreas or insulin pump therapy (serving as controls), followed by a 3-day washout period before switching to 5 days of the intervention not originally assigned.
The artificial pancreas system consisted of an Apple iPhone 4s to run the control algorithm in an app, connected to a G4 Platinum continuous glucose monitor (CGM; Dexcom) via a custom hardware interface. Doses of insulin and glucagon were delivered through insulin infusion sets every 5 minutes by t:slim infusion pumps (Tandem Diabetes Care). Camp physicians and clinical staff members administered the insulin pump therapy; children also wore a CGM during the control period. Researchers recorded mean CGM-measured glucose concentration and the proportion of time with a CGM-measured glucose concentration less than 3.3 mmol/L on days 2 to 5. No restrictions were placed on participants for diet or activity.
Children in the bionic pancreas group had lower mean glucose concentration on days 2 to 5 vs. controls (7.6 vs. 9.3 mmol/L; P = .00037) and spent a lower mean proportion of time with a glucose concentration less than 3.3 mmol/L vs. controls (1.2% vs. 2.8%; P < .0001). During 95 participant days, there were 54 carbohydrate interventions given for hypoglycemia to children in the bionic pancreas group vs. 92 for controls.
There were no recorded episodes of severe hypoglycemia during the study period; five children in the control group experienced medium to large concentrations of ketones (ranging from 0.6-3.6 mmol/dL) on seven occasions; there were no reports of elevated ketones in the artificial pancreas group (P = .063).
In commentary accompanying the study, Bruce Buckingham, MD, professor of pediatrics at Lucile Salter Packard Children’s Hospital and Stanford School of Medicine, and Trang Ly, PhD, FRACP, MBBS, clinical assistant professor of pediatrics at Stanford School of Medicine, noted that the bionic pancreas system is unique in that it does not require carbohydrates to be counted, but only that the user enter whether the meal is typical in size, with the algorithm adapting insulin delivery.
“The investigators’ present study extends [previous] findings to children aged 6 to 11 years, showing that a bihormonal controller can maintain excellent overnight glucose control in this age group,” Buckingham and Ly wrote. “With the bihormonal system, mean glucose concentrations were improved compared with other insulin-only systems, but it did not eliminate sensor-measured hypoglycemia.” – by Regina Schaffer
For more information:
Edward Damiano, PhD, can be reached at the Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston, MA 02215; email: firstname.lastname@example.org.
Disclosure: Russell and Damiano report receiving loaned equipment, support-in-kind and technical assistance from Dexcom and Tandem Diabetes Care. Russell reportsreceiving lecture fees from Abbott Diabetes Care, Eli Lilly, Sanofi-Aventis and Tandem Diabetes Care; and serving on advisory boards for Companion Medical and Tandem Diabetes Care. He also holds a pending patent application for a blood glucose control system. Damiano holds a patent related to a fully automated control system for type 1 diabetes and pending patent applications related to a blood glucose control system, all assigned to Boston University, and reports receiving lecture fees from Dexcom, Tandem Diabetes Care, and Eli Lilly. Please see the full study and accompanying commentary for the other authors’ relevant financial disclosures.