Outpatient Glycemic Control with a Bionic Pancreas in Type 1 Diabetes

Abstract

BACKGROUND The safety and effectiveness of automated glycemic management have not been tested in multiday studies under unrestricted outpatient conditions. METHODS In two random-order, crossover studies with similar but distinct designs, we 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. RESULTS Among the adults, the mean plasma glucose level over the 5-day bionic-pancreas period was 138 mg per deciliter (7.7 mmol per liter), and the mean percentage of time with a low glucose level (<70 mg per deciliter [3.9 mmol per liter]) was 4.8%. After 1 day of automatic adaptation by the bionic pancreas, the mean (±SD) glucose level on continuous monitoring was lower than the mean level during the control period (133±13 vs. 159±30 mg per deciliter [7.4±0.7 vs. 8.8±1.7 mmol per liter], 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 per deciliter [7.7±1.0 vs. 8.7±1.5 mmol per liter], 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). CONCLUSIONS 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. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others; ClinicalTrials.gov numbers, NCT01762059 and NCT01833988.)

A Simple Composite Metric for the Assessment of Glycemic Status from Continuous Glucose Monitoring Data: Implications for Clinical Practice and the Artificial Pancreas

“…22,23 As discussed by Russell et al subjects in the closed loop arm of a bionic pancreas study had lower mean glucose and significantly improved overall glycemic control than subjects in the open loop arm. 20 Analysis with the PGS composite metric shows over two-fifths of study subjects achieved a quality of glycemic control characteristic of patients without diabetes. Both the PGS composite index and its component elements may be helpful as an additional tool analyzing artificial pancreas clinical data and leading to still further improvements in the quality of glycemic control with artificial pancreas devices.…”

“…Finally, the glycemic variability metric was applied to data obtained from a recently published study of artificial pancreas comparing results from open loop and from closed loop in adolescents (n = 32) and in adults (n = 20). 20 Results Figure 2 shows the value of the PGS composite index values for the adult subjects (n = 204) from the feasibility, prepivotal, and pivotal studies of the original G4 Platinum and the modified G4 Platinum (software 505) continuous glucose monitoring system. These data have been separated into three cohorts: subjects without diabetes, subjects with type 2 diabetes, and subjects with type 1 diabetes.…”

“…20 Figure 6 using the PGS composite index shows the dramatic improvement in glycemic control achieved by approximately three-quarters of the subjects, but also highlights the need for further reducing the glycemic variability and occurrence of hypoglycemic events in the remaining one-quarter of subjects in the closed loop arm. In the open loop data, there were eight hypoglycemic episodes £54 mg/dL and four additional episodes <70 mg/dL.…”

Insulin delivery and nocturnal glucose control in children and adolescents with type 1 diabetes

“…A dual-hormone closed-loop system was studied over 5 day-and-nights in adolescents in a diabetes camp using conventional insulin pump therapy as comparator [43]. Mean overnight sensor glucose was significantly reduced during the closed-loop use, the percentage of time spent with low sensor glucose readings was similar during the two interventions, and the percentage of time in target range was greater with closed loop.…”

Technology to Reduce Hypoglycemia

“…These use control algorithms to control insulin delivery in response to sensor glucose. Some systems use insulin as well as glucagon in dual hormone artificial pancreas (AP) systems, 55 although clinical applicability at present for bi-hormonal systems is limited due to lack of stable glucagon preparations. Numerous studies have emerged testing AP control algorithms initially under clinical research settings, 56 subsequently to controlled diabetes camp use 55,57 and now being brought to home use.…”