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 strategy would regulate glucose levels through the infusion of two hormones: insulin and glucagon.

The main objective of this project is to compare the efficacy of single-hormone and dual-hormone closed-loop strategy to regulate overnight glucose levels in a in-patient study in type 1 diabetes adults with hypoglycemia unawareness and documented nocturnal hypoglycemia.

The investigators hypothesized that dual-hormone closed-loop strategy is more effective in regulating overnight glucose levels compared to single-hormone closed-loop strategy.

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 strategy would regulate glucose levels through the infusion of two hormones: insulin and glucagon.

The investigators aim to conduct the 1st randomized cross-over trial comparing single- hormone and dual-hormone closed-loop strategy to regulate overnight glucose levels. The investigators aim to compare the two interventions for 10 hours in two subgroups of adults with type 1 diabètes. Patients from both subgroups will present documented nocturnal hypoglycemia. One subgroup will consist of patients with hypoglycemia unawareness while the other subgroup will consist of patients with hypoglycemia unawareness. This study will allow to determine if there is a greater benefit of a closed-loop strategy in a higher-risk hypoglycemia unaware group.

Inclusion Criteria:

1. Males and females ≥ 18 years of old.
2. Clinical diagnosis of type 1 diabetes for at least one year.
3. The subject will have been on insulin pump therapy for at least 3 months.
4. HbA1c ≤ 12%.
5. Hypoglycemia awareness or unawareness assessed by a questionnaire.
6. Documented NH during the run-in period.

Exclusion Criteria:

1. Clinically significant nephropathy, neuropathy or retinopathy as judged by the investigator.
2. Recent (< 6 months) acute macrovascular event e.g. acute coronary syndrome or cardiac surgery.
3. Pregnancy.
4. Severe hypoglycemic episode within two weeks of screening.
5. Current use of glucocorticoid medication (except low stable dose).
6. Known or suspected allergy to the trial products or snack contents.
7. Other serious medical illness likely to interfere with study participation or with the ability to complete the trial by the judgment of the investigator.
8. Anticipating a significant change in exercise regimen between admissions (i.e. starting or stopping an organized sport).
9. Failure to comply with team's recommendations (e.g. not willing to eat snacks, not willing to change pump parameters, etc).