The CGM-OGTT Glycemic Homeostasis Study

NCT07288372 | Not Yet Recruiting DMC

• 1 other identifier: 20251120
• Study Type: observational
• Target: 225
• Locations: 0 countries
• Sites: N/A

Brief Summary

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).

Conditions

Glucose Metabolism Disorders; Type 2 Diabetes

Keywords

Continuous Glucose Monitoring; CGM; Oral Glucose Tolerance Test; OGTT; Mixed-Meal Tolerance Test; Glycemic Variability; Incretins; Home-Based Testing; GLP-1; GIP

Outcome Measures

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).

  MMTT: 0-3 hours post-meal (for AUC calculation). OGTT: 0, 30, 60, 120, and 180 minutes (for plasma glucose values).

Secondary Outcomes (23)

• Glycemic Variability (GV)

  Entire CGM monitoring period (10-14 days)

• Dietary Macronutrient Intake Composition

  From enrollment until the completion of the in-clinic OGTT (approximately 10-14 days).

• Caloric Intake per Meal

  From enrollment until the completion of the in-clinic OGTT (approximately 10-14 days).

• Mean Amplitude of Glycemic Excursions (MAGE)

  Entire CGM monitoring period (10-14 days)

• Complexity of Glucose Time Series

  Entire CGM monitoring period (10-14 days)

Study Arms (3)

Normal Glucose Tolerance (NGT)

Participants with normal glucose tolerance as defined by a 2-hour plasma glucose value \< 7.8 mmol/L during the oral glucose tolerance test (OGTT).

Pre-diabetes (Pre-DM)

Participants with pre-diabetes (intermediate hyperglycemia) as defined by a 2-hour plasma glucose value between 7.8 mmol/L and 11.0 mmol/L during the OGTT.

Newly Diagnosed Type 2 Diabetes (T2DM)

Participants with newly diagnosed type 2 diabetes as defined by a 2-hour plasma glucose value ≥ 11.1 mmol/L during the OGTT.

Eligibility Criteria

• Age: 18 Years - 70 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study 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).

You may qualify if:

• To be eligible to participate in this study, an individual must meet ALL of the following criteria:
• Is aged between 18 and 70 years, inclusive.
• And meets at least ONE of the following conditions:
• 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.

You may not qualify if:

• An individual who meets ANY of the following criteria will be excluded from participation in this study:
• 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).
• Pregnant or lactating women, or women planning to become pregnant during the study period.
• Known allergy to soy (as the standardized meal may contain soy-based components).

Sponsors & Collaborators

• Shanghai 6th People's Hospital: lead

MeSH Terms

Conditions

Diabetes Mellitus, Type 2; Glucose Metabolism Disorders

Condition Hierarchy (Ancestors)

Diabetes Mellitus; Metabolic Diseases; Nutritional and Metabolic Diseases; Endocrine System Diseases

Study Officials

• Jian Zhou

  Shanghai Sixth People's Hospital, Shanghai, Shanghai 200233

  STUDY CHAIR

Central Study Contacts

Jian Zhou, PhD

CONTACT

+86 021 24056515; zhoujian@sjtu.edu.cn

Yue Zhang, Master's Degree

CONTACT

+86 17851180860; zyzy931@sjtu.edu.cn

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator, Professor, Chief Physician, Head of Department

Study Record Dates

• First Submitted: December 4, 2025
• First Posted: December 17, 2025
• Study Start: December 18, 2025
• Primary Completion (Estimated): January 1, 2027
• Study Completion (Estimated): August 10, 2027
• Last Updated: December 23, 2025

Record last verified: 2025-12

Data Sharing

• IPD Sharing: Will not share