The CGM-OGTT Glycemic Homeostasis Study
Trial statusNot yet recruiting
Trial phaseNot listed
Trial typeObservational
Biological sexAll
Age18-70
SponsorShanghai 6th People's Hospital
About this trial
This is a prospective, exploratory, observational study aimed at investigating the mechanisms of glycemic homeostasis by comparing continuous glucose monitoring (CGM) data with results from the oral glucose tolerance test (OGTT).
The study plans to enroll approximately 225 participants aged 18-70 years who are at risk for or suspected of having glucose metabolism disorders, but without a prior diagnosis of diabetes. Participants will be equipped with a blinded CGM device for 10-14 days. During this period, they will perform two standardized mixed-meal tolerance tests (MMTT) at home. Subsequently, they will undergo a standard 75g OGTT at the hospital, where blood samples will be collected at multiple time points to measure glucose, insulin, C-peptide, and gastrointestinal hormones (GLP-1, GIP).
Based on the 2-hour blood glucose value from the OGTT, participants will be naturally categorized into three groups for comparative analysis: Normal Glucose Tolerance (NGT), Pre-diabetes (Pre-DM), and Newly Diagnosed Type 2 Diabetes (T2DM).
The primary objective is to establish a quantitative relationship between CGM-derived parameters (e.g., glycemic variability, time-in-range) after the MMTT and the OGTT diagnostic results. Secondary objectives include assessing the feasibility and correlation between home-based MMTT and standard OGTT, exploring the impact of gastrointestinal hormone responses on daily glucose fluctuations, and investigating the association between postprandial glucose dynamics and vascular reactivity (e.g., postprandial hypotension).
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
Is aged between 18 and 70 years, inclusive.
Presents with diabetes-related clinical symptoms or signs (e.g., unexplained ·polydipsia, polyphagia, polyuria, weight loss) and has been advised by a ·clinician to undergo an OGTT for diagnostic clarification.
Has indicators of abnormal glucose metabolism:Impaired Fasting Glucose (IFG): Fasting venous plasma glucose ≥ 6.1 mmol/L and < 7.0 mmol/L.and/or Glycated hemoglobin (HbA1c) in the pre-diabetes range of 5.7% to 6.4%.
Has at least one of the following diabetes risk factors:Body Mass Index (BMI) ≥ 24 kg/m²；Has a first-degree relative (parent, sibling, or child) with a history of diabetes；Has a history of hypertension (or undergoing antihypertensive treatment) or dyslipidemia.
Disqualifiers
Previously diagnosed with diabetes.
Use of medications that significantly affect glucose metabolism or gastrointestinal hormones (e.g., GLP-1 receptor agonists, DPP-4 inhibitors, glucocorticoids) within a specified washout period prior to enrollment.
History of gastrointestinal surgery (e.g., gastrectomy) or chronic pancreatic disease.
Presence of severe hepatic or renal impairment (e.g., ALT > 3 times the upper limit of normal, or eGFR < 45 mL/min/1.73m²).
Trial population
This monocentric, prospective, observational study will enroll 225 adult participants (aged 18-70 years) who are at high risk for diabetes or present with abnormal glucose metabolism, but have not been previously diagnosed with diabetes. Participants must meet specific eligibility criteria, including having diabetes-related symptoms, impaired fasting glucose, elevated HbA1c in the pre-diabetes range, or established risk factors (e.g., obesity, family history of diabetes, hypertension, or dyslipidemia). Key Exclusion Criteria include a prior diagnosis of diabetes, use of medications affecting glucose metabolism, significant organ dysfunction, or pregnancy. Upon enrollment, all participants will undergo a standardized 75g Oral Glucose Tolerance Test (OGTT). Based on the OGTT results, they will be retrospectively categorized into three natural groups for comparative analysis: Normal Glucose Tolerance (NGT), Pre-Diabetes (Pre-DM), and Newly Diagnosed Type 2 Diabetes (T2DM).
Trial design
Design model
Cohort
Time perspective
Prospective
Treatments tested in this trial
Not listed
Trial groups
225 Participants
are grouped into 3 trial groupsGroup A: Normal Glucose Tolerance (NGT)
Group B: Pre-diabetes (Pre-DM)
Group C: Newly Diagnosed Type 2 Diabetes (T2DM)
Trial outcomes
Primary outcomes
1
Correlation between MMTT-induced glucose AUC and OGTT plasma glucose values
To establish a quantitative relationship by assessing the correlation between the area under the curve (AUC) of postprandial glucose derived from Continuous Glucose Monitoring (CGM) after a standardized Mixed-Meal Tolerance Test (MMTT) and the plasma glucose values at all standard time points during the Oral Glucose Tolerance Test (OGTT).
Time frame
MMTT: 0-3 hours post-meal (for AUC calculation). OGTT: 0, 30, 60, 120, and 180 minutes (for plasma glucose values).Secondary outcomes
1
Glycemic Variability (GV)
Coefficient of variation (CV) of glucose levels, calculated from Continuous Glucose Monitoring (CGM) data.
Time frame
Entire CGM monitoring period (10-14 days)2
Dietary Macronutrient Intake Composition
The daily intake proportion of macronutrients (carbohydrates, protein, and fat), expressed as a percentage of total caloric intake, assessed via a dietary logging application.
Time frame
From enrollment until the completion of the in-clinic OGTT (approximately 10-14 days).3
Caloric Intake per Meal
The average energy intake (in kilocalories) per meal, estimated using a dietary logging application.
Time frame
From enrollment until the completion of the in-clinic OGTT (approximately 10-14 days).4
Mean Amplitude of Glycemic Excursions (MAGE)
Mean Amplitude of Glycemic Excursions, calculated from CGM data to quantify major glucose swings.
Time frame
Entire CGM monitoring period (10-14 days)Locations
Sponsors and contacts
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Source ClinicalTrials.gov
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