Background: Multivariable artificial pancreas (mAP) systems are developed to supplement the continuous glucose monitoring (CGM) data with physiological measurements from wearable devices and automatically incorporate physical activity information in proactive insulin dose decisions. The wearable devices incorporated into mAP systems collect data in real-time to determine the type and intensity of the physical activity without requiring manual entries. As the first mAP, our multivariable Automated Insulin Delivery (mAID) system does not require user input for meals or exercise. In silico studies and clinical experiments have shown improvement in glycemic control with mAID during unannounced physical activity compared to the glucose-only AP systems.
Methods: mAID is evaluated in three clinical experiments, with one experiment conducted in a crossover fashion where the glucose-only AP is compared with the mAID. The experiments involved two subjects (1 male and 1 female) with T1DM, age 35 - 45 years, bodyweight 70 - 110 kg, total daily insulin of 35 - 80 U, and insulin-to-carb ratio 6.5 - 7 g/U. The experiments included meals and medium-intensity exercises (treadmill run and stationary bike) without any announcements to the system. The target glycemic range was [70, 180] mg/dL.
Results: The mAID system regulated glycemia more effectively, than the glucose-only AP, which had 13.33% of time spend below 70 mg/dL and 86.67% of time spent in the target range, with a significant 55 g of rescue carbs given to avert impending low glucose. The mAID system resulted in all time spent in the target range for the same subject. Across the closed-loop experiments, subjects spent a total of 87.69% of time in the target range.
Conclusions: The mAID system supplements the CGM data with real-time physiological data to automatically handle physical activity and maintain tight glycemic control.
M. Rashid: None. M. Sevil: None. N. Hobbs: None. I. Hajizadeh: None. M. Askari: None. R. Brandt: None. M. Park: None. L.T. Quinn: None. A. Cinar: Research Support; Self; Dexcom, Inc., JDRF. Stock/Shareholder; Self; Dexcom, Inc., Eli Lilly and Company, Insulet Corporation, Medtronic, Novo Nordisk A/S, Tandem Diabetes Care.
National Institutes of Health (1DP3DK101075-01, 1DP3DK101077-01); JDRF (A18-0036-001)