Glucose outcomes of a learning-type artificial pancreas with an unannounced meal in type 1 diabetes

Comput Methods Programs Biomed. 2020 Jul:191:105416. doi: 10.1016/j.cmpb.2020.105416. Epub 2020 Feb 26.

Abstract

Background and objectives: Glycemic control with unannounced meals is the major challenge for artificial pancreas. In this study, we described the performance and safety of learning-type model predictive control (L-MPC) for artificial pancreas challenged by an unannounced meal in type 1 diabetes (T1D).

Methods: This closed-loop (CL) system was tested in 29 T1D patients at one site in a 4 h inpatient open-label study. Participants used an L-MPC CL system for 6 days after 2-day system identification using open-loop (OL) insulin system. During the CL period, the L-MPC system was started from 8:00 am to noon each day. At 9:00 am, each participant consumed 50 g of carbohydrates with no prandial insulin bolus. At 9:30 am on CL-Day 4 or CL-Day 6, participants rode bicycles for 20 minutes or drank 50 ml of beer, in a random order.

Results: As the primary outcome, TIR on CL-Day 3 was 65.2±23.3%, which was 9.8 points higher (95% CI 1.8 to 17.8; P = 0.019) than that on CL-Day 1. The time of glucose >10 mmol/L was decreased by 11.0% (95% CI -18.7 to 3.3; P = 0.007), and mean glucose level was decreased by 1.1 mmol/L (95% CI -1.1 to 0.5; P = 0.000). The total daily insulin dosage showed no significant difference (-0.1U, 95% CI -1.34 to 1.32; P = 0.982). Compared with OL-Day1 with a postprandial bolus, the TIR was increased by 13.7 points (95% CI 1.4 to 26.0; P = 0.030), the time of glucose >10 mmol/L and the mean glucose level were also decreased. Compared with the exercise day (CL-Day E, 62.0 ± 23.3%; P = 0.347) or alcohol day (CL-Day A, 64.0 ± 23.6%; P = 0.756), there was no statistically significant difference in terms of TIR, time of glucose >10 mmol/L and mean glucose level. No severe hypoglycemic events occurred and hypoglycemic episodes were not increased by using closed-loop insulin system.

Conclusion: The L-MPC CL insulin system achieved good glycemic control challenged by an unannounced meal.

Keywords: Artificial pancreas; Closed-loop insulin system; Learning, Unannounced meal.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Algorithms
  • Blood Glucose* / analysis
  • Diabetes Mellitus, Type 1*
  • Female
  • Humans
  • Insulin Infusion Systems / standards*
  • Machine Learning*
  • Male
  • Meals*
  • Middle Aged
  • Outcome Assessment, Health Care
  • Pancreas, Artificial* / statistics & numerical data
  • Young Adult

Substances

  • Blood Glucose