Outpatient Glycemic Control With a Bionic Pancreas in Type 1 Diabetes

Study Questions:

What is the efficacy of an autonomous, wearable, bihormonal, bionic pancreas in two distinct outpatient settings?


In two random-order, crossover studies with similar but distinct designs, the investigators compared glycemic control with a wearable, bihormonal, automated, “bionic” pancreas (bionic-pancreas period) with glycemic control with an insulin pump (control period) for 5 days in 20 adults and 32 adolescents with type 1 diabetes mellitus. The automatically adaptive algorithm of the bionic pancreas received data from a continuous glucose monitor to control subcutaneous delivery of insulin and glucagon. The prespecified coprimary outcomes for the adult study were the mean plasma glucose level (obtained every 2 hours) and the mean percentage of time that the patient had a low glucose level (<70 mg/dl) during the bionic-pancreas period. Comparisons between study groups were performed with the paired-sample, heteroskedastic Student’s t-test.


Among the adults, the mean plasma glucose level over the 5-day bionic-pancreas period was 138 mg/dl (7.7 mmol/L), and the mean percentage of time with a low glucose level (<70 mg/dl [3.9 mmol/L]) was 4.8%. After 1 day of automatic adaptation by the bionic pancreas, the mean (± standard deviation) glucose level on continuous monitoring was lower than the mean level during the control period (133 ± 13 vs. 159 ± 30 mg/dl [7.4 ± 0.7 vs. 8.8 ± 1.7 mmol/L], p < 0.001) and the percentage of time with a low glucose reading was lower (4.1% vs. 7.3%, p = 0.01). Among the adolescents, the mean plasma glucose level was also lower during the bionic-pancreas period than during the control period (138 ± 18 vs. 157 ± 27 mg/dl [7.7 ± 1.0 vs. 8.7 ± 1.5 mmol/L], p = 0.004), but the percentage of time with a low plasma glucose reading was similar during the two periods (6.1% and 7.6%, respectively; p = 0.23). The mean frequency of interventions for hypoglycemia among the adolescents was lower during the bionic-pancreas period than during the control period (one per 1.6 days vs. one per 0.8 days, p < 0.001).


The authors concluded as compared with an insulin pump, a wearable, automated, bihormonal, bionic pancreas improved mean glycemic levels, with less frequent hypoglycemic episodes, among both adults and adolescents with type 1 diabetes mellitus.


The bionic pancreas reduced mean levels of plasma glucose and blood glucose on continuous glucose monitoring, as compared with insulin-pump therapy, even though approximately 75% of the patients had better glycemic control at baseline than national averages. Limitations of the bionic pancreas include a risk of hypoglycemia if acetaminophen ingestion leads to overestimation of the blood glucose level. As the bionic pancreas improved glycemic control, it delivers more insulin to adult patients who had poor control during the period of usual care, and the balance of risks and benefits associated with delivering more insulin to achieve more physiologic glycemic control will require further study. Overall, the use of the bihormonal bionic pancreas resulted in better glycemic control than is possible with the current standard of care, and is an exciting therapeutic prospect that needs further investigation.

< Back to Listings