Assessment of the Efficacy of the Artificial Pancreas Combined With a Qualitative Meal Size Estimation to Control Postprandial Glucose Levels

Summary

Postprandial glycemic excursions are major determinants of overall glycemic control in type 1 diabetes. Carbohydrate content of ingested meals is the main determinant of post-meal glucose excursion. Accurate carbohydrate counting is a critical aspect of managing postprandial blood glucose levels. accurate carbohydrate counting is considered by patients as a significant burden and frustrating task.

The closed-loop system (CLS) 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.

The objective of this study is to compare the efficacy of two strategies to regulate glucose levels in outpatient settings in adults with type 1 diabetes: 1) single-hormone CLS with rapid acting insulin analogue combined with carbohydrate counting; 2) single-hormone CLS with rapid acting insulin analogue combined with simplified qualitative meal-size estimation.

A sub-study will also be proposed to participants. Postprandial exercise combines two situations complicating CLS operation: a high plasma insulin due to insulin on-board related to meal boluses and rapid blood glucose changes (postprandial blood glucose excursion and then drop during exercise) making input from the glucose sensor less accurate. The objective of this sub-study will be to explore the safety and efficacy of the CLS using the combined strategy of pre-meal exercise announcement and meal bolus reduction of 33% when exercise is performed 1 hour compared to 2 hours post meal time.

Conditions

• Type 1 Diabetes

Interventions

DEVICE

Single-hormone closed-loop system

Every 10 minutes, the glucose levels as measured by the sensor will be transferred automatically to a LG Google Nexus Smartphone that the algorithm is running on, which will calculate the recommended doses and will send them wirelessly to the infusion pump.

DEVICE

Insulin pump

Tandem Diabetes Care

DEVICE

Continuous glucose monitoring system

Dexcom G6

DRUG

Aspart or Lispro

Aspart or lispro will be infused with the infusion pump

OTHER

Carbohydrate counting

Participants will be required to enter an estimate of the carbohydrate content of their meal into the phone. Insulin boluses will be calculated based on grams of carbohydrates and participant's insulin-to-carbohydrate ratio. Carbohydrate-matching full prandial bolus will be given 5 to 10 minutes before the meal.

OTHER

Simplified qualitative meal-size estimation strategy

A pre-meal partial prandial bolus will be given 5-10 minutes before the meal. The partial bolus will be based on the estimated meal size (small, regular, large and extra-large). The closed-loop system will give the remaining insulin needed based on the sensor readings. For this strategy, meal size will be defined as: small as any meal less than 30g, regular meal as any meal between 30g and 60g CHO, large meal as any meal between 60g and 90g CHO, extra-large meal for anything above 90g CHO.

OTHER

3-week intervention

Glucose levels will be regulated by the single-hormone closed-loop system for 3 consecutive weeks.

OTHER

1-hour postprandial exercise (sub-study)

60 minute exercise will be started one hour after the meal time.

OTHER

2-hour postprandial exercise (sub-study)

60 minute exercise will be started two hours after meal time

OTHER

Exercise announcement and meal bolus reduction (sub-study)

Meal bolus reduction of 33% at meal time and exercise announcement (increased target glucose from 6 to 9mmolL) to the CLS algorithm

Sponsors & Collaborators

• Institut de Recherches Cliniques de Montreal

  lead OTHER

Principal Investigators

• Rémi Rabasa-Lhoret · Montreal Clinical Research Institute

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2020-07-10

Primary Completion

2021-11-27

Completion

2021-12-14

Countries

• Canada

Study Locations