Comparison of Closed-loop Operation After Morning Meal With and Without Carbohydrate Counting

An Open-label, Randomized Two-way, Cross-over Study to Compare Meal-and-carbohydrate-announcement Strategy Versus Meal-announcement Strategy During Closed-loop Regulation of Glucose Levels in a Morning Meal in Adults 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 dosage based on the sensor's readings. A dual-hormone closed-loop system would regulate glucose levels through the infusion of two hormones: insulin and glucagon.

The main goal of this project is to assess whether a dual-hormone closed-loop strategy would alleviate the burden of carbohydrate counting from patients with type 1 diabetes (T1D) without a significant degradation in post-meal glucose control.

Each patient will be admitted twice to a clinical research facility. In one visit, patients will eat a morning meal accompanied with a matching insulin bolus (depending on the carbohydrate content of the meal) and glucose levels will be subsequently regulated using dual-hormone closed-loop system. In the other visit, patients will eat the same meal but will inject only a partial insulin bolus (not depending on carbohydrate content of the meal) and the remaining needed insulin will be delivered based on glucose sensor excursions as part of closed-loop operation. If post-meal glucose levels were indifferent between the two visits, then this would suggest that carbohydrate counting may not be necessary during closed-loop operation as the closed-loop system will give any remaining insulin needed to cover the glucose absorbed from the meal. Twelve subjects will be enrolled in this study.

Inclusion Criteria:

• Males and females ≥ 18 and ≤ 65 years of old.
• Clinical diagnosis of type 1 diabetes for at least one year. The diagnosis of type 1 diabetes is based on the investigator's judgment and medical history (e.g. history of acido-ketosis, etc.); C peptide level and antibody determinations are not needed.
• The subject will have been on insulin pump therapy for at least 3 months.
• Last (less than 3 months) HbA1c ≤ 12%.

Exclusion Criteria:

• Clinically significant nephropathy, neuropathy (especially clinically significant gastroparesis) or retinopathy as judged by the investigator.

• Recent (< 3 months) acute macrovascular event e.g. acute coronary syndrome or cardiac surgery.

• Pregnancy.

• Severe hypoglycemic episode within two weeks of screening.

  • Medication likely to affect with the interpretation of the results: Prandase, Victoza, Byetta and Symlin

• Known or suspected allergy to the trial products or meal contents.

• Other serious medical illness likely to interfere with study participation or with the ability to complete the trial by the judgment of the investigator.

• Failure to comply with team's recommendations (e.g. not willing to eat snack, not willing to change pump parameters, etc).

• Unreliable carbohydrate counting

• Problems with venous access