Closed-loop Control of Overnight Glucose Levels in Adults and Adolescents With Type 1 Diabetes

Closed-loop strategy is composed of three components: glucose sensor to read glucose levels, insulin pump to infuse insulin and a dosing mathematical algorithm to decide on the required insulin dosages based on the sensor's readings. A dual-hormone closed-loop system would regulate glucose levels through the infusion of two hormone: insulin and glucagon.

The main objective of this project is to compare the efficacy of single-hormone closed-loop strategy, dual-hormone closed-loop strategy and pump therapy to regulate overnight glucose levels in a out-patient study in adults and adolescents with type 1 diabetes.

The investigators hypothesized that dual-hormone closed-loop strategy is more effective in regulating overnight glucose levels in adults and adolescents with type 1 diabetes compared to single-hormone closed-loop strategy, which in turn is more effective than the conventional pump therapy.

Closed-loop strategy is composed of three components: glucose sensor to read glucose levels, insulin pump to infuse insulin and a dosing mathematical algorithm to decide on the required insulin dosages based on the sensor's readings. A dual-hormone closed-loop system would regulate glucose levels through the infusion of two hormone: insulin and glucagon.

We aim to conduct a multicenter study to compare the efficacy of conventional pump therapy, single-hormone closed-loop strategy and dual-hormone closed-loop strategy to regulate overnight glucose levels, at home, in adolescents and adults with type 1 diabetes. Each intervention will be tested on two nights: 1) After a carbohydrate-rich dinner meal (to exaggerate hyperglycemic risk and; 2) After an evening exercise (to exaggerate hypoglycemic risk).

Eligibility Criteria:
Inclusion Criteria:

* Males and females aged ≥ 12 years of old.
* Body mass index \< 35
* Clinical diagnosis of type 1 diabetes for at least one year.
* The subject will have been on insulin pump therapy for at least 4 months.
* HbA1c \< 12%.
* At least two visits with an endocrinology team in the past 1 year.

Exclusion Criteria:

* Clinically significant nephropathy, neuropathy (peripheral or autonomic e.g. significant gastroparesis) or retinopathy as judged by the investigator.
* Recent (\< 6 months) acute macrovascular event e.g. acute coronary syndrome or cardiac surgery.
* A recent injury to body or limb, muscular disorder, use of any medication or other significant medical disorder if that injury, medication or disease in the judgment of the investigator will affect the completion of the exercise protocol.
* Ongoing pregnancy.
* Severe hypoglycemic episode within two weeks of screening.
* Current use of glucocorticoid medication (except low stable dose and inhaled therapy).
* Known or suspected allergy to the insulin aspart, glucagon, Medtronic sensors, or Medtronic infusion sets..
* Other serious medical illness likely to interfere with study participation or with the ability to complete the trial by the judgment of the investigator.
* Anticipating a significant change in treatment regimen between admissions (such as a major change in an exercise routine, significant change in dietary routine or in insulin therapy.
* Failure to comply with team's recommendations.