Glucose-responsive insulin and glucagon delivery (dual-hormone artificial pancreas) in adults with type 1 diabetes: a randomized crossover controlled trial

Abstract

Background: Most patients with type 1 diabetes do not achieve their glycemic targets. We aimed to assess the efficacy of glucose-responsive insulin and glucagon closed-loop delivery for controlling glucose levels in adults with type 1 diabetes.

Methods: We conducted a randomized crossover trial involving 15 adults with type 1 diabetes, comparing standard insulin-pump therapy with dual-hormone, closed-loop delivery. Patients were admitted twice to a clinical research facility and received, in random order, both treatments. Each 15-hour visit (from 1600 to 0700) included an evening exercise session, followed by a medium-sized meal, a bedtime snack and an overnight stay. During visits that involved closed-loop delivery, basal insulin and glucagon miniboluses were delivered according to recommendations based on glucose sensor readings and a predictive dosing algorithm at 10-minute intervals. During visits involving standard insulin-pump therapy (control visits), patients used conventional treatment.

Results: Dual-hormone closed-loop delivery increased the percentage of time for which patients' plasma glucose levels were in the target range (median 70.7% [interquartile range (IQR) 46.1%-88.4%] for closed-loop delivery v. 57.3% [IQR 25.2%-71.8%] for control, p = 0.003) and decreased the percentage of time for which plasma glucose levels were in the low range (bottom of target range [< 4.0 mmol/L], 0.0% [IQR 0.0%-3.0%] for closed-loop delivery v. 10.2% [IQR 0.0%-13.0%] for control, p = 0.01; hypoglycemia threshold [< 3.3 mmol/L], 0.0% [IQR 0.0%-0.0%] for closed-loop delivery v. 2.8% [IQR 0.0%-5.9%] for control, p = 0.006). Eight participants (53%) had at least 1 hypoglycemic event (plasma glucose < 3.0 mmol/L) during standard treatment, compared with just 1 participant (7%) during closed-loop treatment (p = 0.02).

Interpretation: Dual-hormone, closed-loop delivery guided by advanced algorithms improved short-term glucose control and reduced the risk of hypoglycemia in a group of 15 adults with type 1 diabetes.

Trial registration: ClinicalTrials.gov, no. NCT01297946.

Figure 1:

Flow of participants through the crossover study, showing the crossover in therapies between visits 1 and 2. The crossed-over streams are shown in parallel on each side of the flow chart. IQR = interquartile range, VO_2max = maximum oxygen uptake.

Figure 2:

Profiles (medians and interquartile ranges) of (A) plasma glucose concentration and (B) basal insulin infusion with dual-hormone closed-loop delivery and continuous subcutaneous insulin infusion. (C) The histogram of glucagon delivery during closed-loop delivery.

Figure 3:

Profiles (medians and interquartile ranges) of plasma glucose concentration and basal insulin infusion before and after receipt of glucagon bolus (n = 61 boluses).