Benefits of Retained Insulin for Good Health (BRIGHT)

September 15, 2026 updated by: Royal Devon and Exeter NHS Foundation Trust

Understanding the Impact of Endogenous Insulin Secretion on Clinical Outcomes in Type 1 Diabetes and the Optimal Approach to C-peptide Measurement for Outcome Prediction

The purpose of this research is to understand the impact of retained endogenous insulin (as measured by C-peptide) on quality of life and related outcomes in people living with insulin treated diabetes, and, in those living with type 1 diabetes, to determine the pragmatic and non-pragmatic C-peptide measures which have the strongest association with clinical benefit (including repeated home samples and derived measures of beta cell function). The investigators will do this in two ways:

Firstly, the investigators will extend a large existing prospective study of new adult onset diabetes (Getting the Right Classification and Treatment From Diagnosis in Adults With Diabetes (StartRight)) https://clinicaltrials.gov/ct2/show/NCT03737799) which has followed 1800 participants for median 4 years from diabetes diagnosis. Participants with insulin treated diabetes will be invited to take part in a further research visit remotely or face to face. The investigators will assess the longitudinal relationship between C-peptide and the available quality of life, mental health status and healthcare utilisation measures over up to 9 years from diabetes diagnosis and assess additional measures in cross sectional analysis.

In the second part of this research, the investigators will utilise cohorts of over 2500 participants with type 1 diabetes, measured C-peptide and consent to recontact to recruit 200 participants with a range of C-peptide. Eligible participants with C-peptide measured in clinical care may also be invited to take part. The investigators will undertake detailed assessment of complex and pragmatic measures of C-peptide and beta cell function and compare performance in predicting glycaemic outcomes (using data from continuous glucose monitors) and (where relevant) patient reported outcomes.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

The purpose of this study is to understand the possible benefits of restoring insulin secretion in people living with diabetes, and to understand how insulin secretion can be best measured in people living with diabetes.

Most people living with type 1 diabetes stop making their own insulin, this means that insulin injections are needed to survive. It also means their blood glucose is variable, meaning it is very difficult to control blood glucose levels. This is in contrast to type 2 diabetes, where most people keep making their own insulin, and loss of insulin production is uncommon.

Previous research has shown that some people with type 1 diabetes keep making some of their own insulin, and this can be very helpful for their blood glucose control. However, there is limited information on long term benefits of making insulin, and other possible benefits, such as on wellbeing, have not been studied. It is important that the full benefits of making insulin are known as new treatments have been developed to preserve insulin secretion in type 1 diabetes, and/or to restore insulin secretion. These treatments are expensive and can have side effects, and have been studied only in small studies for a short amount of time. It is important to fully understand the likely long-term benefits of preserving or restoring insulin secretion to know whether healthcare providers like the NHS should fund these treatments.

At present research studies that are testing new treatments to preserve or restore a person's insulin production need to frequently test insulin secretion, using a test called a mixed meal tolerance test that needs to be undertaken in a hospital setting and takes at least 2.5 hours. This makes these studies difficult to take part in, and expensive to run. Insulin production can now be measured at home, on a finger-prick test, but more information is needed on the best way to do the home test for these kinds of studies.

This research has two parts. In the first part of this research the investigators will measure insulin secretion (using a test called C-peptide) in 500 people with insulin treated diabetes who have already taken part in a large recent study that measured their insulin secretion, and other important measures such as their quality of life and use of healthcare services, every year for up to 4 years after diabetes diagnosis. There will be assessment of participants' quality of life and other measures related to diabetes. The investigators will use this information, and the information already collected in the study, to understand the effects of retaining or loosing insulin production over up to 9 years from diabetes diagnosis, and compare whether this differs in type 1 and 2 diabetes.

In the second part of this research the investigators will recruit 200 participants with type 1 diabetes who have had their insulin secretion measured in part one of this research, in other research or in clinical care. Information from this previous testing will be used to ensure participants are recruited with a range of insulin production. Participants will attend a research facility for assessment of their insulin production over 2 hours after a liquid meal similar to a milkshake. Participants will then undertake this test at home, using finger-prick samples after the same liquid meal, and after 3 of their own normal meals. Participants will also monitor their glucose over 2 weeks using a device called a continuous glucose monitor. This information will be used to understand if home measures are as accurate as the test in the research facility, and work as well in predicting a person's risk of low glucose (hypoglycaemia) and how variable their glucose is.

The end result of this research will be important information to inform the design of studies of new treatments to preserve or restore insulin secretion for people living with diabetes and understand the likely long-term benefits of these treatments.

Study Type

Observational

Enrollment (Estimated)

700

Contacts and Locations

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

Study Contact

Study Locations

  • United Kingdom
      • Bath, United Kingdom, BA1 3NG
        • Recruiting
        • D1 Wolfson Centre Research and Development
        • Contact:
        • Principal Investigator:
          • Rachel Mathias
      • Bristol, United Kingdom, BS10 5NB
        • Recruiting
        • Clinical Research Centre
        • Principal Investigator:
          • Georgina Russell
        • Contact:
    • Cornwall
      • Truro, Cornwall, United Kingdom, TR1 3LJ
        • Recruiting
        • Diabetes and Endocrine Centre
        • Principal Investigator:
          • Duncan Browne
        • Contact:
    • Devon
      • Exeter, Devon, United Kingdom, EX2 5DW
        • Recruiting
        • NIHR Exeter Clinical Research Facility
        • Contact:
        • Principal Investigator:
          • Angus Jones

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

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

ARM 1: Participants who have previously taken part in the StartRight study (NCT03737799) with consent to re-contact for future research (from sites across the United Kingdom (UK)).

ARM 2: Participants who have previously taken part in the StartRight study or other diabetes research cohorts, as well as patients referred by their clinician or self-referred (across the UK).

Description

ARM 1

Inclusion Criteria:

  • Previously recruited to the StartRight study (NCT03737799) with consent to be contacted for further research
  • Clinical diagnosis of diabetes & Insulin treated
  • Able and willing to provide informed consent/assent.
  • Aged 18 years or older.

ARM 2

Inclusion Criteria:

  • Clinical diagnosis of Type 1 diabetes
  • Known C-peptide, measured as part of previous research or as part of diabetes clinical care OR Where C-peptide is not measured, participant must be within 7 years of diagnosis and have at least 1 positive islet antibody, measured at any time since diabetes diagnosis.
  • Where measured C-peptide is >600pmol/L, previous positive islet autoantibodies.
  • Able and willing to provide informed consent
  • Aged 18 years or older

Exclusion Criteria:

- Renal failure defined by eGFR <30mL/min/1.73 m²

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

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Arm 1
Adults (aged >= 18 years) diagnosed with diabetes for >3 years, treatment with insulin, and previously taken part in the StartRight study with consent to re-contact.
Other: Observational
Observational
Arm 2
Adults (aged >= 18 years) diagnosed with type 1 diabetes. Known level of insulin secretion, measured using a C-peptide test after diabetes diagnosis. Participants will have had C-peptide measured as part of a previous research study or as part of their diabetes clinical care. Where C-peptide is not measured, participant must be within 7 years of diagnosis and have at least 1 positive islet antibody, measured at any time since diabetes diagnosis.
Other: Observational
Observational

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Capillary C-peptide measured 1-5 hours after a meal containing carbohydrates (Arm 1)
Time Frame: 1 day during study participation
Analysis of Arm 1 will assess the relationship between home post-meal C-peptide (measured serially from within 12 months of diagnosis up to 10 years post-diagnosis, through extension of an existing study), and the secondary outcomes listed below. This will be assessed as longitudinal change over time (Arm 1 cohort) and cross-sectionally using the most recent visit data from the combined Arm 1 and Arm 2 cohorts.
1 day during study participation
Plasma and capillary C-peptide (Arm 2)
Time Frame: 90-minutes post baseline
Primary analysis for Arm 2 will assess the relationship between home capillary C-peptide measurements (post-meal, assessed individually & as the average of up to three measurements, and 90-minute post-mixed meal tolerance test) and 90-minute plasma C-peptide measured during a mixed meal tolerance test conducted at a research centre. Secondary analysis will compare the relationship between C-peptide measures and the continuous glucose monitoring secondary outcome listed below.
90-minutes post baseline

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Questionnaire assessed hypoglycaemia and hypoglycaemia unawareness (Arm 1 & Arm 2)
Time Frame: Symptoms experienced during 4 weeks prior to study enrolment
Results from analysis of data from Modified Clarke/Edinburgh Hypoglycaemia History questionnaire
Symptoms experienced during 4 weeks prior to study enrolment
Questionnaire assessed emotional burden (Arm 1 & Arm 2)
Time Frame: Symptoms experienced during 4 weeks prior to study enrolment
Results from analysis of data from Diabetes Distress Scale questionnaire
Symptoms experienced during 4 weeks prior to study enrolment
Questionnaire assessed quality of life/wellbeing (Arm 1 & Arm 2)
Time Frame: Symptoms experienced during 4 weeks prior to study enrolment
Results from analysis of data from Veterans RAND 12-Item Health Survey (VR-12) questionnaire
Symptoms experienced during 4 weeks prior to study enrolment
Changes/updates to diabetes treatment, complications and healthcare utilisation for relevant medical conditions since previous study visit (Arm 1)
Time Frame: Up to 3 years prior to study enrolment
Data collected during current study visit combined with data from previous study visit.
Up to 3 years prior to study enrolment
Continuous glucose monitor measured glucose variability and hypoglycaemia (Arm 2)
Time Frame: 14 days during study participation
Analysis for Arm 2 will compare the relationship of different C-peptide measures to glucose variability (assessed as Standard Deviation glucose) and hypoglycaemia (assessed as % time glucose below 3mmol/L), derived from 14 days of continuous interstitial glucose monitoring
14 days during study participation

Collaborators and Investigators

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

Sponsor

Royal Devon and Exeter NHS Foundation Trust

Collaborators

University of Birmingham
University of Exeter

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 (Actual)

October 31, 2025

Primary Completion (Estimated)

April 30, 2027

Study Completion (Estimated)

June 30, 2027

Study Registration Dates

First Submitted

August 11, 2026

First Submitted That Met QC Criteria

September 15, 2026

First Posted (Actual)

September 18, 2026

Study Record Updates

Last Update Posted (Actual)

September 18, 2026

Last Update Submitted That Met QC Criteria

September 15, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2507771
  • 2-SRA-2025-1637-S-B (Other Grant/Funding Number: Breakthrough T1D (formerly Juvenile Diabetes Research Foundation (JDRF)))

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

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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