Clinical Characteristics of People With Long-term Type 1 Diabetes

Study Overview
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Brief Summary
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Type 1 diabetes (T1D) is characterized by absolute insulin deficiency. Although the discovery and application of exogenous insulin has prolonged the lifespan of T1D patients, the chronic diabetic complications caused by long-term poor glycemic control will still reduce patients' quality of life and the overall life expectancy. According to the studies focused on long-term T1D, part of the patients with long disease duration showed resistance to microvascular complications, and several protective factors have been identified. The prevalence of T1D in China is extremely low compared to that in the western world, and little is known about the characteristics of patients with long-term T1D in China. Therefore, this study is designed to collect variable clinical and laboratory features of patients with long-term T1D, explore the risk and protective factors for the development of microvascular complications, and provide reference for the prediction and prevention of these complications.

Detailed Description
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This is a single-center, prospective, observational study. The investigators propose to enroll 400 patients with type 1 diabetes (T1D) ≥10 years. The patients will be followed up annually for 3 years. In order to ensure high quality data, two staff are responsible for the input of original data into the database to check and confirm the accuracy. When the data entered by two people is inconsistent, the auxiliary staff decides which data to use. Missing data will be filled in with the multiple imputation method. The regression analysis will be used to explore the risk and protective factors for the development and progression of microvascular complications.

Official Title
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Clinical Characteristics of People With Long-term Type 1 Diabetes: a Cohort Study

Conditions
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Type 1 Diabetes

Intervention / Treatment
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* Biological: Chronic hyperglycemia
* Biological: Residual islet function
* Genetic: Genetic variation
* Dietary Supplement: Dietary constitutes
* Genetic: Microbiome composition and function
* Biological: Metabolome composition
* Biological: Composition of peripheral blood immune cells


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Individuals diagnosed with type 1 diabetes(T1D) according to the 1999 World Health Organization report Insulin dependence from disease onset with T1D duration of ≥10 years able to understand the procedures and methods of this study, voluntarily participate in the study, and agree to sign the informed consent form Exclusion Criteria: patients with type 2 diabetes, gestational diabetes, or specific types of diabetes patients with mental disability or have any other condition or disease that may hamper compliance with the protocol
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| long-term T1D<br>Subjects who has the T1D duration ≥10 years, with or without diabetic complications. | Biological: Chronic hyperglycemia<br>* For each follow-up, the glycated albumin(GA) reflecting glycemic control of the past 2-3 weeks, the glycated hemoglobin(HbA1c) reflecting glycemic control of the past 2-3 months, and the advanced glycation end products(AGEs) will be measured.<br>Biological: Residual islet function<br>* For each follow-up, fasting and stimulated C-peptide levels will be measured.<br>Genetic: Genetic variation<br>* Genetic variations of interest will be detected with the blood sample collected at baseline.<br>Dietary Supplement: Dietary constitutes<br>* For each follow-up, the dietary constitutes for the past 3 days will be recorded.<br>Genetic: Microbiome composition and function<br>* For each follow-up, the fecal and oral samples will be collected for measurement.<br>Biological: Metabolome composition<br>* For each follow-up, the serum and urine samples will be collected for measurement.<br>Biological: Composition of peripheral blood immune cells<br>* For each follow-up, the peripheral blood mononuclear cells will be collected for measurement.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| the development or progression of diabetic nephropathy | measured by urine microalbumin/creatinine | from May 2022 to December 2025 | 
| the development or progression of diabetic retinopathy | diagnosed by an ophthalmologist based on fundus photography | from May 2022 to December 2025 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| the changes of memory function | measured by the Auditory Verbal Learning Test (AVLT) | from May 2022 to December 2025 | 
| the changes of executive function | measured by the Shape Trail Test (STT) | from May 2022 to December 2025 | 
| the changes of language function | measured by the Boston Naming Test (BNT) | from May 2022 to December 2025 | 
| the changes on magnetic resonance imaging(MRI) | the MRI reflects the changes of cerebral structure and functional connectivity | from May 2022 to December 2025 | 
| the changes of bone mineral density(BMD) | measured by dual x-ray absorbtiometry(DXA), indicating bone density | from May 2022 to December 2025 | 
| the changes of brachial-ankle pulse wave velocity(baPWV) | measured by ultrasound, indicating large artery stiffness | from May 2022 to December 2025 | 
| the changes of carotid intima-media thickness(IMT) | measured by ultrasound, indicating the form of carotid atherosclerotic plaque | from May 2022 to December 2025 |