Studies offer support for home use of artificial pancreas in type 1 diabetes

Home use of a closed-loop insulin delivery system, or artificial pancreas, appeared to be effective in patients with type 1 diabetes, according to 2 recently published reports conducted under regular living conditions.

The first report, which was published online Sep. 17 by the New England Journal of Medicine, compared closed-loop insulin delivery with sensor-augmented pump therapy (SAP) in in 2 multicenter, crossover randomized controlled studies of patients with type 1 diabetes. Thirty-three adults used the closed-loop system during the day and during the night, while 25 children and adolescents used it overnight. Both the closed-loop system and SAP were used for 12 weeks each. The study's primary end point was the time during which the glucose level was between 70 mg/dL and 180 mg/dL (3.9 mmol/L and 10.0 mmol/L) for adults and between 70 mg/dL and 145 mg/dL (3.9 mmol/L and 8.1 mmol/L) for children and adolescents.

Time spent in the target glucose range was 11 percentage points greater with the closed-loop system than with SAP among adults during day and night (P<0.001) and 24.7 percentage points greater among children and adolescents during nighttime (P<0.001). Mean glucose level and mean HbA1c were also significantly lower during the closed-loop phase among adults, and mean nighttime glucose level was significantly lower among children and adolescents. During the closed-loop phase, 3 severe episodes of hypoglycemia occurred when the closed-loop system was not being used (i.e., the closed-loop system was not turned on and the pump was not connected). The authors concluded that based on their results, use of a closed-loop system at home without close supervision is feasible in adults, children, and adolescents who have type 1 diabetes.

A second study, also a crossover design, published online Sept. 30 by Lancet Diabetes & Endocrinology, randomly assigned 34 patients 18 to 69 years of age who had type 1 diabetes and used insulin pumps to artificial pancreas use from dinnertime until they awakened in the morning plus patient-managed SAP during the day, or to SAP use only. The study had a 2-week run-in period; after 2 patients dropped out in the first study week, 17 were initially assigned to the control period and 15 were initially assigned to the artificial pancreas period.

Once the run-in period was completed, all patients used SAP (insulin-pump treatment and continuous glucose monitoring) for 2 sessions each lasting 8 weeks. In each of the 8-week sessions, half of the patients used a closed-loop system involving an artificial pancreas that calculated how much insulin would be infused from dinnertime until morning. Between the 2 sessions, during a 4-week washout period, patients followed their regular prestudy treatment using the study pump with or without continuous glucose monitoring. The study's primary endpoint was percentage of time spent in the target glucose concentration range (3.9 to 10.0 mmol/L [70 mg/dL to 180 mg/dL]) from 8:00 p.m. to 8:00 a.m. HbA1c was a secondary outcome.

During weeks 3 to 8 of the interventions, patients in the artificial pancreas group spent more time in the target glucose range each night than patients in the SAP group (66.7% vs. 58.1%; paired difference, 8.6%; 95% CI, 5.8% to 11.4%; P<0.0001), due to reductions in mean time spent in both hyperglycemia and hypoglycemia. HbA1c decreased significantly more in the artificial pancreas period than in the control period (−0.3% vs. −0.2%; paired difference, −0.2%; 95% CI, −0.4 to −0.0; P=0.047). No serious adverse events were noted. The authors concluded that home use of an artificial pancreas is safe and beneficial for patients with type 1 diabetes and noted that effects on HbA1c are “encouraging but preliminary.”

The author of an editorial that accompanied the Lancet Diabetes & Endocrinology study pointed out that potential barriers to adherence, such as comfort and fear of technology, still need to be addressed. “A better understanding of how these barriers affect adherence to [artificial pancreas] treatment will be the key step in making this technology an option for patients with type 1 disease,” the editorialist wrote.