Multicenter outpatient dinner/overnight reduction of hypoglycemia and increased time of glucose in target with a wearable artificial pancreas using modular model predictive control in adults with type 1 diabetes

Aims: To test in an outpatient setting the safety and efficacy of continuous subcutaneous insulin infusion (CSII) driven by a modular model predictive control (MMPC) algorithm informed by continuous glucose monitoring (CGM) measurement. Methods: 13 patients affected by type 1 diabetes participated to a non-randomized outpatient 42-h experiment that included two evening meals and overnight periods (in short, dinner&night periods). CSII was patient-driven during dinner & night period 1 and MMPC-driven during dinner&night period 2. The study was conducted in hotels, where patients could move around freely. A CGM system (G4 Platinum; Dexcom Inc., San Diego, CA, USA) and insulin pump (AccuChek Combo; Roche Diagnostics, Mannheim, Germany) were connected wirelessly to a smartphone-based platform (DiAs, Diabetes Assistant; University of Virginia, Charlottesville, VA, USA) during both periods. Results: A significantly lower percentage of time spent with glucose levels<3.9mmol/l was achieved in period 2 compared with period 1: 1.96±4.56% vs 12.76±15.84% (mean±standard deviation, p<0.01), together with a greater percentage of time spent in the 3.9-10mmol/l target range: 83.56±14.02% vs 62.43±29.03% (p=0.04). In addition, restricting the analysis to the overnight phases, a lower percentage of time spent with glucose levels<3.9mmol/l (1.92±4.89% vs 12.7±19.75%; p=0.03) was combined with a greater percentage of time spent in 3.9-10mmol/l target range in period 2 compared with period 1 (92.16±8.03% vs 63.97±2.73%; p=0.01). Average glucose levels were similar during both periods. Conclusions: The results suggest that MMPC managed by a wearable system is safe and effective during evening meal and overnight. Its sustained use during this period is currently being tested in an ongoing randomized 2-month study.