The addition of glucagon delivery to a closed-loop system with automated exercise detection reduces hypoglycemia in physically active adults with type 1 diabetes.
Aims
Exercise increases risk of hypoglycemia in type 1 diabetes (T1D). An artificial pancreas (AP) can help mitigate this risk. We tested whether adjusting insulin and glucagon in response to exercise within a dual-hormone AP reduces exercise-related hypoglycemia.
Materials and Methods
In random order, 21 adults with T1D underwent three 22 h sessions: AP with exercise dosing adjustment (APX), AP with no exercise dosing adjustment (APN), and sensor-augmented pump therapy (SAP). After an overnight stay and 2 hours after breakfast, participants exercised for 45 minutes at 60% of their maximum heart rate with no snack given before exercise. During APX, insulin was decreased and glucagon was increased at exercise onset, while during SAP, subjects could adjust dosing before exercise. The two primary outcomes were percent of time in hypoglycemia (<3.9 mmol/L) and percent of time in euglycemia (3.9–10 mmol/L) from the start of exercise to the end of the study.
Results
The mean times spent in hypoglycemia (<3.9 mmol/L) after the start of exercise were 0.3% [−0.1, 0.7%] for APX, 3.1% [0.8, 5.3%] for APN, and 0.8% [0.1, 1.4%] for SAP. There was an absolute difference of 2.8% less time in hypoglycemia in APX versus APN (p =0.001) and 0.5% less time in hypoglycemia for APX versus SAP (p = 0.16). Mean time in euglycemia was comparable across conditions.
Conclusions
Adjusting insulin and glucagon delivery at exercise onset within a dual-hormone AP significantly reduces hypoglycemia compared with no adjustment and performs similarly to SAP when insulin is adjusted before exercise.
OBJECTIVE
To assess the efficacy and feasibility of a dual-hormone (DH) closed-loop system with insulin and a novel liquid stable glucagon formulation compared with an insulin-only closed-loop system and a predictive low glucose suspend (PLGS) system.
RESEARCH DESIGN AND METHODS
In a 76-h, randomized, crossover, outpatient study, 23 participants with type 1 diabetes used three modes of the Oregon Artificial Pancreas system: 1) dual-hormone (DH) closed-loop control, 2) insulin-only single-hormone (SH) closed-loop control, and 3) PLGS system. The primary end point was percentage time in hypoglycemia (<70 mg/dL) from the start of in-clinic aerobic exercise (45 min at 60% VO2max) to 4 h after.
RESULTS
DH reduced hypoglycemia compared with SH during and after exercise (DH 0.0% [interquartile range 0.0–4.2], SH 8.3% [0.0–12.5], P = 0.025). There was an increased time in hyperglycemia (>180 mg/dL) during and after exercise for DH versus SH (20.8% DH vs. 6.3% SH, P = 0.038). Mean glucose during the entire study duration was DH, 159.2; SH, 151.6; and PLGS, 163.6 mg/dL. Across the entire study duration, DH resulted in 7.5% more time in target range (70–180 mg/dL) compared with the PLGS system (71.0% vs. 63.4%, P = 0.044). For the entire study duration, DH had 28.2% time in hyperglycemia vs. 25.1% for SH (P = 0.044) and 34.7% for PLGS (P = 0.140). Four participants experienced nausea related to glucagon, leading three to withdraw from the study.
CONCLUSIONS
The glucagon formulation demonstrated feasibility in a closed-loop system. The DH system reduced hypoglycemia during and after exercise, with some increase in hyperglycemia.
The aim of this pilot study was to investigate the effect of exercise on sleep and nocturnal hypoglycaemia in adults with type 1 diabetes (T1D). In a 3-week crossover trial, 10 adults with T1D were randomized to perform aerobic, resistance or no exercise. During each exercise week, participants completed 2 separate 45-minutes exercise sessions at an academic medical center. Participants returned home and wore a continuous glucose monitor and a wrist-based activity monitor to estimate sleep duration. Participants on average lost 70 (±49) minutes of sleep (P = .0015) on nights following aerobic exercise and 27 (±78) minutes (P = .3) following resistance exercise relative to control nights. The odds ratio with confidence intervals of nocturnal hypoglycaemia occurring on nights following aerobic and resistance exercise was 5.4 (1.3, 27.2) and 7.0 (1.7, 37.3), respectively. Aerobic exercise can cause sleep loss in T1D possibly from increased hypoglycaemia.
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