Postprandial meal glucose control with closed-loop systems (CLS) still needs some improvements. In the postprandial period, sensor delay in detecting blood glucose rise after a meal together with delays in insulin absorption expose patients to early risk of hyperglycemia and then to late-postprandial hypoglycemia. Glucagon infusion in dual-hormone CLS has the potential to improve post-meal control as compared to single-hormone CLS allowing a better glucose excursion related to a more aggressive insulin infusion while minimizing hypoglycemic risk. Several approaches have been tested for the determination of prandial boluses during closed-loop operation. The objective of this study is to test in outpatient unrestricted settings whether, in the context of closed-loop strategy, conventional meal carbohydrate counting could be reduced to a simplified qualitative meal size estimation without a significant degradation in overall glycemic control in adult patients with type 1 diabetes. The investigators hypothesize that in outpatient free-living conditions: 1) Dual-hormone CLS with partial boluses is equivalent to dual-hormone CLS with full boluses in terms of mean glucose; 2) Single-hormone CLS with partial boluses is equivalent to single-hormone CLS with full boluses in terms of mean glucose. Secondary hypothesis are: 3) Dual-hormone CLS with partial boluses will decrease time in hypoglycemia compared to single-hormone CLS with partial boluses; 4) Dual-hormone CLS with partial boluses is better than sensor-augmented pump therapy in terms of mean glucose; 5) Single-hormone CLS with partial boluses is better than sensor-augmented pump therapy in terms of mean glucose.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
15
Interventions will be conducted in outpatient settings. Subject's usual insulin will be used. Meals will not be standardized. Subjects will be allowed to eat whatever and when they want and will be allowed to drink alcohol. Subjects will be allowed to exercise, but they will be asked to do the same amount and intensity of exercise on all intervention visits. Subjects will be accompanied all the time by a member from the research team during closed-loop visits to implement hormonal infusions.
Patient's usual insulin (Lispro, Aspart or guilisine) will be used in all interventions.
In the dual-hormone CLS interventions, glucagon (Eli Lilly) will be used.
Every 10 minutes, the glucose level as measured by the real time sensor (Dexcom G4 Platinum, Dexcom) will be entered manually into the computer. The pumps' infusion rate will then be changed manually based on the computer generated recommendation infusion rates. The computer generated recommendations are based on a predictive algorithm.
Institut de recherches cliniques de Montréal
Montreal, Quebec, Canada
Mean glucose levels as measured by the glucose sensor.
The following comparisons will be done: 1) Dual-hormone CLS with partial boluses vs. dual-hormone CLS with full boluses; 2) Single-hormone CLS with partial boluses vs. single-hormone CLS with full boluses.
Time frame: 15 hours
Mean glucose levels as measured by the glucose sensor
The following comparisons will be done: 1) Dual-hormone CLS with partial boluses vs. single-hormone CLS with partial boluses; 2) Dual-hormone CLS with partial boluses vs. sensor-augmented pump therapy; 3) Single-hormone CLS with partial boluses vs. sensor-augmented pump therapy.
Time frame: 15 hours
Percentage of time of sensor glucose concentrations between 4 and 8 mmol/L
Time frame: 15 hours
Percentage of time of sensor glucose concentrations between 4 and 10 mmol/L
Time frame: 15 hours
Percentage of time of sensor glucose concentrations above 10 mmol/L
Time frame: 15 hours
Percentage of time of sensor glucose concentrations above 14 mmol/L
Time frame: 15 hours
Percentage of time of glucose levels spent below 4 mmol/L
Time frame: 15 hours
Percentage of time of glucose levels spent below 3.1 mmol/L
Time frame: 15 hours
Area under the curve of glucose values below 4 mmol/L
Time frame: 15 hours
Area under the curve of glucose values below 3.1 mmol/L
Time frame: 15 hours
Number of patients with at least one hypoglycemic event below 3.1 mmol/L with or without symptoms
Time frame: 15 hours
Total number of hypoglycemic event below 3.1 mmol/L
Time frame: 15 hours
Total insulin delivery
Time frame: 15 hours
Total glucagon delivery
Time frame: 15 hours
Standard deviation of glucose levels
Time frame: 15 hours
Total carbohydrate intake
Time frame: 15 hours
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.