Overnight Control with Single-Hormone and Dual-Hormone Artificial Pancreas Systems in Type 1 Diabetes: An Outpatient Randomized Trial—Preliminary Results

Abstract

The addition of subcutaneous glucagon to artificial pancreas systems may provide an additional countermeasure to hypoglycemia. In an ongoing randomized, crossover, multicentre trial comparing overnight outpatient interventions with dual-hormone (insulin and glucagon) artificial pancreas (DHAP), single-hormone (insulin) artificial pancreas (SHAP) and conventional pump therapy (CSII), we have studied 10 of 28 patients with type 1 diabetes. Each patient completed 6 10-hour study nights (2 nights per intervention). The first night of each intervention was preceded by a 90–110 g CHO standardized meal, while the second night was preceded by a 60 minute exercise session followed by a 60–80 g CHO standardized meal. The primary outcome was the proportion of time spent in target range (4.0–8.0 mmol/L as measured by the glucose sensor) from 11 p.m.–7 a.m. Preliminary analysis in 10 subjects (7 male, 3 female; age 28–69 years; mean A1c 7.5%) showed that relative to CSII, both DHAP and SHAP increased the time spent in target range (DHAP 76.4%, SHAP 72.6%, CSII 49.9%; p=NS for SHAP vs. DHAP, otherwise p<0.01). DHAP was associated with the smallest risk of hypoglycemia (% time spent <4.0 mmol/L for DHAP 5.0%, SHAP 19.7%, CSII 27.9%; p=NS for CSII vs. SHAP, otherwise p<0.01). Hypoglycemia requiring oral treatment (<3.3 mmol/L if symptomatic, otherwise <3.0 mmol/L) occurred in 5 CSII nights compared to 4 SHAP nights and 1 DHAP night. Preliminary results suggest that SHAP and DHAP are equally superior to CSII at regulating overnight glucose levels, but that an artificial pancreas strategy incorporating glucagon may have additional benefits in reducing hypoglycemia.