DROPLeT Study
Research type
Research Study
Full title
Defining The Rate Of Progression Of Late Onset Type 1 Diabetes
IRAS ID
261315
Contact name
Angus Jones
Contact email
Sponsor organisation
Royal Devon & Exeter NHS Foundation Trust
Duration of Study in the UK
2 years, 0 months, 1 days
Research summary
"Research Summary"
Background
Type 1 diabetes occurs when the body’s immune system destroys the cells that make insulin. It has often been thought of as a disease of young people, but recent work has shown that about half of cases occur after age 30. There has been little research into Type 1 diabetes in this age group - in part because, with increasing age, Type 2 diabetes is much more common. This makes Type 1 diabetes occurring in older adults much harder to identify so misdiagnosis (Type 2 diabetes misclassified as Type 1 diabetes, or Type 1 diabetes misclassified as Type 2) is common.
A main focus of research in Type 1 diabetes in recent years has been to develop early treatments to slow the progression of the disease by preserving a patient’s own insulin secretion. Loss of insulin secretion occurs as part of Type 1 diabetes. It has been shown that preserving insulin secretion leads to less variable blood sugar levels and lower rates of complications. To date, these early intervention studies have usually focussed on young adults under age 30 (or in some cases children). A key reason that older adults have not been included is that it has been thought that Type 1 diabetes in older adults is a milder disease and does not progress rapidly. This would mean these treatments may not be needed or that studies would have to go on for too long to show differences in insulin secretion. Our research has suggested this is not true, and that adults diagnosed with Type 1 diabetes at an older age have rapid progression and severe disease similar to that seen in younger adults. If this is the case, older adults could be included in studies of treatments to slow diabetes progression. This would greatly help these studies, as recruiting patients has been a major challenge.Study Aims & Participation
The aim of this research is to find out if older adults (aged over 30) with Type 1 diabetes have similar rates of progression to young adults (aged under 30). To do this, we will recruit 113 participants diagnosed with Type 1 diabetes at over 30 years of age and a comparison group of 51 participants diagnosed with Type 1 diabetes between the age of 18 and 30 years. All participants will have been diagnosed with Type 1 diabetes by their doctor in the previous 100 days and will be insulin treated.
Participants will attend a baseline visit having fasted (nothing to eat or drink except water) since the night before and complete a consent form. We will insert a cannula into their vein (a small tube that enables us to collect repeat blood samples without repeatedly inserting a needle) and collect baseline blood samples. Participants will then drink a milkshake and we will collect blood samples from the cannula to measure their insulin secretion every 30 minutes for two hours, this is called a mixed meal tolerance test. We will also ask participants to complete a questionnaire, collect information about their diabetes diagnosis and treatment and measure their height and weight. We will repeat this mixed meal tolerance test after 6 months and 1 year to examine how quickly their insulin secretion falls.
We will also ask volunteers to do finger prick measures of insulin secretion at their own homes (performed in similar manner to finger prick glucose testing) at baseline, 3, 6, 9 and 12 months. This is to see if a simple test that participants can do at home can be used to easily identify those with rapidly decreasing insulin secretion. We will compare how quickly participants lose their own insulin secretion in each age group and also examine how we can best identify older participants who will rapidly progress.
If this research shows that older participants also rapidly lose insulin secretion, they could be included in future trials of treatments to preserve insulin secretion. This would greatly help the development of effective treatments, as it is often difficult for these studies to find enough participants. It would also provide early information to support development of future research into Type 1 diabetes in older adults. This would include research to help correctly diagnose Type 1 diabetes in adults, and to understand why people with the same risk can develop diabetes at very different ages.
"summary of results"
1) Remote recruitment strategy
The original recruitment plan focused on identifying and enrolling participants at local sites. Since diagnosing type 1 diabetes in adults can be challenging, our primary pre-registered outcomes (NCT04682457) were based on confirming the diagnosis by detecting positive islet-autoantibodies. Due to the Covid-19 pandemic, we shifted to remote recruitment, allowing for nationwide participation across the UK. This included self-referrals made possible through collaboration with the UK Type 1 Diabetes Research Consortium. As a result, we recruited a higher proportion of individuals with islet-autoantibodies. This allowed us to reach our target of islet-autoantibody-confirmed type 1 diabetes by recruiting 131 clinically diagnosed participants, compared to the original goal of 196.2) In adults with type 1 diabetes loss of insulin secretion is unaffected by age of diagnosis
Using both mixed meal tolerance tests (MMTT) and home-based C-peptide tests (a marker of insulin secretion), we found no difference in the one-year rate of C-peptide loss between those diagnosed at ages 18-30 and those diagnosed after age 30, which was the primary outcome of the study (findings submitted as an abstract to the Diabetes UK Conference 2025). Both groups experienced a similar decline, losing about one-third of their insulin production each year. This suggests that age does not significantly influence the rate of insulin secretion loss in adults with type 1 diabetes. Crucially, this finding supports the inclusion of older adults in intervention studies aimed at slowing or stopping type 1 diabetes progression, which has typically focused on younger adults. Expanding eligibility to include older adults could help address recruitment challenges in type 1 diabetes research, significantly increasing the pool of potential participants for new therapy trials.3) Blood Glucose Variability Measured by Continuous Glucose Monitoring (CGM) can predict retained insulin secretion
Recent UK guidelines recommend that all people with type 1 diabetes use continuous glucose monitors (CGMs), making CGM data readily available in diabetes clinics. We investigated how well CGM metrics correlate with C-peptide levels to determine whether this data could help identify individuals with severe insulin deficiency. We found a strong correlation between CGM metrics and C-peptide levels, showing that CGM data combined with routine clinical features (such as BMI) could reliably predict retained insulin secretion (C-peptide ≥200 pmol/l) with an AUC of 0.98. This is significant, as Foteinopoulou et al. (Diabetic Medicine, 2021) found that 13% of individuals in type 1 diabetes clinics had C-peptide levels ≥200 pmol/l. These patients, with retained insulin secretion, may benefit from non-insulin treatments and, in some cases, can even discontinue insulin therapy. Our findings suggest that CGM data could be a valuable tool for clinicians to identify patients with preserved insulin secretion, allowing for treatment optimization and potentially improved outcomes.
4) Home measurement of insulin secretion is possible
Recruiting people with newly diagnosed type 1 diabetes for research requiring in-clinic tests is often difficult due to work commitments, travel, or health issues. To address this, we tested whether offering home appointments with phone support could improve recruitment and make study participation more convenient. Of the 131 participants recruited, 85% opted for the home-testing protocol. At each study visit, over 90% of participants successfully returned viable samples. Participant feedback indicated that this approach was well-received and practical, with 85% expressing willingness to participate in another fully remote study. This remote method could be a valuable strategy for future studies on insulin secretion, helping to enhance recruitment and participation.REC name
Wales REC 7
REC reference
19/WA/0232
Date of REC Opinion
18 Sep 2019
REC opinion
Further Information Favourable Opinion