Defining the Decline in Endogenous Insulin Secretion in Type 1 Diabetes Diagnosed After 30 Years of Age.

Completed

• Conditions: Diabetes Mellitus, Type 1; Progression

• Registration Number: NCT04682457
• Lead Sponsor: Royal Devon and Exeter NHS Foundation Trust

Brief Summary

The study aims is to find out if people with type 1 diabetes diagnosed in later life (after age 30) have the same rapid loss of insulin secretion (measured using C-peptide) that occurs in younger adults with type 1 diabetes. The investigators will recruit 135 participants aged over 30 years with a clinical diagnosis of type 1 diabetes and diabetes duration ≤100 days. The investigators will also recruit a comparison group of 61 participants aged 18-30 with a clinical diagnosis of type 1 diabetes and diabetes duration ≤100 days. C-peptide will be measured during mixed meal tolerance tests (MMTT) performed at baseline, 6 months and a year.

This study also aims to test a new more practical way of monitoring insulin secretion at home using a finger prick 'blood spot' rather than time consuming tests in a hospital. Finger-prick C-peptide samples will be collected after the MMTT and by the participants at home throughout the year.

Detailed Description

The study aims to evaluate progression of type 1 diabetes. Primary analysis will be conducted on those with \>=1 diabetes autoantibody positive (GAD, IA2 ZNT8). Sensitivity analysis will be performed by repeating all analysis defining T1D as a) double antibody positivity and b) single antibody positivity combined with a high genetic risk score for T1D (T1DGRS\>5th centile of a control population).

Further aims will be to evaluate the utility of dried blood spot testing to detect change in C-peptide and the utility of home test results as a marker of hypoglycaemia and glucose variability.

Study Timeline

• Study Start: 2019-11-01
• Study First Submitted: 2020-12-15
• Study First Submitted QC: 2020-12-22
• Study First Posted: 2020-12-23
• Primary Completion: 2023-09-01
• Study Completion: 2023-12-31
• Status Verified: 2024-06
• Last Update Submitted: 2024-06-03
• Last Update Posted: 2024-06-04

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 130

Inclusion Criteria

• Adults with a clinical diagnosis of Type 1 diabetes within the previous 100 days.
• Aged >30 at the time of Type 1 diabetes diagnosis OR (additional early onset Type 1 diabetes cohort) aged ≥18 and ≤30 at the time of Type 1 diabetes diagnosis.
• Insulin treated at the time of recruitment
• Able and willing to provide informed consent.

Exclusion criteria

• Pregnancy
• Known monogenic diabetes
• Known secondary diabetes (diabetes considered likely due to medication, cystic fibrosis, pancreatitis, pancreatic cancer, pancreatic surgery, hemochromatosis or Cushing's syndrome).

Exclusion Criteria

Not provided

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
C-peptide value at a year	12 months	12 month (Mixed Meal Tolerance Test) MMTT area under the curve (AUC) C-peptide.
Change in C-peptide over a year	12 months	Rate of change of MMTT AUC C-peptide over 12 months assessed at regular study visits

Secondary Outcome Measures

Name	Time	Method
C-peptide value at 12 months	12 months	Mean C-peptide at 12 months assessed using MMTT and home blood samples
Change in dried blood spot C-peptide	12 months	Rate of change in home dried blood spot C-peptide over 12 months
Glucose variability & hypoglycemia	12 months	Glucose variability \& hypoglycemia as measured by continuous glucose monitoring (CGM)

Trial Locations

Locations (1)

Royal Devon & Exeter NHS Foundation Trust; 🇬🇧 Exeter, Devon, United Kingdom