Closing the Loop for 36 Hours in Adolescents With Type 1 Diabetes: Evaluation of Reduced Meal Bolusing

June 25, 2012 updated by: Dr Roman Hovorka, University of Cambridge

The main focus of our research is the development of a closed-loop system for glucose control in people with type 1 diabetes. After having demonstrated the safety and efficacy of overnight closed-loop insulin delivery, we are extending the evaluation of closed-loop to the daytime. Meal-related insulin dosing can be challenging and prandial insulin overdosing can be associated with the occurrence of postprandial hypoglycaemia, thus representing a confounding factor of hypoglycaemia free glucose control during the day. A further investigation is needed to evaluate alternative strategies for prandial insulin dosing. We will study eight adolescents with type 1 diabetes during closed-loop insulin delivery combined with either standard or reduced insulin doses with the meals, in a randomised crossover design. Stable glucose isotopes will be administered to collect data for modelling of glucose turnover around the meals, during daily activities and overnight.

The information provided by the use of glucose isotopes would be very helpful to increase our understanding of the physiology of glucose turnover and to facilitate the development of an improved control algorithm. Ultimately this study will help with the development of a closed-loop system to match insulin infusions to change in glucose levels in real life conditions.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

8

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United Kingdom
      • Cambridge, United Kingdom, CB20QQ
        • Wellcome Trust Clinical Research Facility, Addenbrooke's Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

12 years to 18 years (Child, Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • The subject is between 12 and 18 years of age (inclusive).
  • The subject has had type 1 diabetes, as defined by WHO for at least 1 year or is confirmed C-peptide negative.
  • The subject will have been on insulin pump user for at least 3 months, with good knowledge of insulin self-adjustment.
  • HbA1c ≤ 12 % based on analysis from central laboratory

Exclusion Criteria:

  • Non-type 1 diabetes mellitus including those secondary to chronic disease
  • Any other physical or psychological disease likely to interfere with the normal conduct of the study and interpretation of the study results
  • Current treatment with drugs known to interfere with glucose metabolism such as systemic corticosteroids, non-selective beta-blockers and MAO inhibitors
  • Known or suspected allergy against insulin
  • Subjects with clinical significant nephropathy, neuropathy or proliferative retinopathy as judged by the clinician
  • Total daily insulin dose >= 2 IU/kg
  • Post-menarchal girls who are pregnant or intending to become pregnant or are breastfeeding
  • Any coexisting cardiac and respiratory condition

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Closed-loop with standard meal insulin bolus
Subcutaneous basal insulin delivery will be adjusted following the advice by a computer-based algorithm, based on subcutaneous sensor glucose readings. Standard meal insulin dosing will be performed at each meal, following individual standard clinical practice.
Device: Closed-loop insulin delivery
Subcutaneous basal insulin delivery will be adjusted following the advice by a computer-based algorithm, based on subcutaneous sensor glucose readings. Standard or reduced meal insulin dosing will be performed in a randomised design.
Experimental: Closed-loop with reduced meal insulin bolus
Subcutaneous basal insulin delivery will be adjusted following the advice by a computer-based algorithm, based on subcutaneous sensor glucose readings. The standard meal insulin dose will be reduced by 20 to 50%.
Device: Closed-loop insulin delivery
Subcutaneous basal insulin delivery will be adjusted following the advice by a computer-based algorithm, based on subcutaneous sensor glucose readings. Standard or reduced meal insulin dosing will be performed in a randomised design.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Primary efficacy endpoint
Time Frame: 36hours
The primary outcome measure is time spent with plasma glucose concentration in the target range (3.9-10.0mmol/L) between 24:00 on Day 1 and 08:00 on Day 3 (32 hours) as obtained with closed-loop insulin delivery in comparison with conventional insulin pump therapy.
36hours

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Secondary efficacy endpoints
Time Frame: 36 hours
  • Total and basal insulin delivery between 24:00 on Day 1 and 08:00 on Day 3 (36 hours)
  • CGM glucose levels between 24:00 on Day 1 and 08:00 on Day 3 (36 hours)
  • Overnight glucose levels between 24:00 on Day 1 and 08:00 on Day 2 (8 hours), and between 24:00 on Day 2 and 08:00 on Day 3 (8 hours)
36 hours

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Cambridge

Collaborators

Cambridge University Hospitals NHS Foundation Trust

Investigators

  • Principal Investigator: Roman Hovorka, PhD, University of Cambridge

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

April 1, 2011

Primary Completion (Actual)

September 1, 2011

Study Completion (Actual)

September 1, 2011

Study Registration Dates

First Submitted

April 5, 2011

First Submitted That Met QC Criteria

June 25, 2012

First Posted (Estimate)

June 27, 2012

Study Record Updates

Last Update Posted (Estimate)

June 27, 2012

Last Update Submitted That Met QC Criteria

June 25, 2012

Last Verified

June 1, 2012

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • DAN02

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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