Closed-loop Control of Postprandial Glucose Levels in Adults With Type 1 Diabetes

Summary

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.

Conditions

• Type 1 Diabetes

Interventions

OTHER

15-hour intervention

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.

DRUG

Insulin (Lispro, Aspart or guilisine)

Patient's usual insulin (Lispro, Aspart or guilisine) will be used in all interventions.

DRUG

Glucagon (Eli Lilly)

In the dual-hormone CLS interventions, glucagon (Eli Lilly) will be used.

OTHER

Closed-loop strategy

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.

Sponsors & Collaborators

• Institut de Recherches Cliniques de Montreal

  lead OTHER

Principal Investigators

• Rémi Rabasa-Lhoret · Institut de recherches cliniques de Montréal

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2015-05-31

Primary Completion

2015-10-31

Completion

2015-10-31

Countries

• Canada

Study Locations