OGTT At Home Using CGM Vs At the Clinic

Not Applicable

Not yet recruiting

• Conditions: Pre-diabetes; Diabetes

• Registration Number: NCT06862128
• Lead Sponsor: Linkoeping University

Brief Summary

This randomized, crossover study evaluates the feasibility and accuracy of a self-administered oral glucose tolerance test (OGTT) at home using continuous glucose monitoring (CGM) compared to a standard clinic-based OGTT. Participants with prediabetes will undergo both home-based and clinic-based OGTTs, with glucose levels measured via CGM and venous plasma glucose. The primary outcome is the correlation between CGM-based glucose values and standard OGTT results. Secondary outcomes include diagnostic agreement, metabolic hormone associations, and feasibility of home-based testing as a diagnostic tool for dysglycemia.

Detailed Description

This study aims to evaluate the feasibility, accuracy, and diagnostic utility of a self-administered oral glucose tolerance test (OGTT) at home using continuous glucose monitoring (CGM) compared to a standard clinic-based OGTT.

Study Design Type: Randomized, crossover study Participants: 75 adults with prediabetes Intervention: Each participant will complete both a home-based OGTT with CGM and a clinic-based OGTT with venous plasma glucose measurement.

Primary Objective To assess the correlation between glucose values obtained from a CGM-based home OGTT and a standard venous OGTT performed in the clinic.

Secondary Objectives Evaluate diagnostic agreement between CGM-derived and venous glucose measurements.

Assess variability in glucose responses between the two methods. Investigate associations between OGTT results and metabolic/sex hormones. Determine feasibility and patient adherence to home-based testing.

Methods Participants will be randomized into two groups: one starting with a clinic-based OGTT, the other with a home-based OGTT, followed by a crossover period. CGM will continuously monitor glucose responses, and standard venous plasma glucose measurements will serve as the reference method.

Clinical Relevance A validated home-based OGTT using CGM could improve access to glucose tolerance testing, reduce patient burden, and enhance early detection of dysglycemia.

Study Timeline

• Status Verified: 2025-03
• Study First Submitted: 2025-03-01
• Study First Submitted QC: 2025-03-01
• Last Update Submitted: 2025-03-01
• Study First Posted: 2025-03-06
• Last Update Posted: 2025-03-06
• Study Start: 2025-04-01
• Primary Completion: 2025-12-31
• Study Completion: 2025-12-31

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 75

Inclusion Criteria

• Prediabetes indicated by both of the following in the past 2 years:
• • ≥1 fasting venous plasma glucose ≥6.1 but ≤6.9 mmol/L OR ≥1 non-fasting venous plasma glucose ≥7.8 but ≤11.0 mmol/L
• • ≥1 HbA1c ≥39 but ≤47 mmol/mol
• Use of GLP-1 receptor agonists or SGLT-2 inhibitors
• Access to a smart phone which is compatible with the CGM application and has working Bluetooth connectivity
• Ability to read and respond to online instructions and questionnaires in Swedish.

Exclusion Criteria

• Previous oral glucose tolerance test (OGTT)
• T2D indicated by any of the following at any time:
• • Fasting venous plasma glucose ≥7.0 mmol/L
• • Non-fasting venous plasma glucose value ≥11.1 mmol/L
• • HbA1c ≥48 mmol/mol
• Previous bariatric surgery e.g., gastric by-pass or gastric sleeve surgery
• Body mass index <25 kg/m2, indicating an increased risk of type 1-diabetes, maturity-onset diabetes of the young or latent autoimmune diabetes in adults
• Body weight <43 kg, which is a contraindication to administer the full OGTT glucose solution according to Swedish guidelines
• Current pregnancy, because gestational diabetes is a unique entity
• Need of regular use of acetaminophen or ascorbic acid supplements during the study period, which may interfere with CGM accuracy33
• Fear of needle sticks
• Involvement in the study design, data collection, analysis, or participant recruitment.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Primary Outcome Measures

Name	Time	Method
The correlation coefficient between the glucose levels of the OGTT-home vs OGTT-clinic	Between OGTT-clinic at baseline vs OGTT-home at each 5-min interval from 0-30 min; Between OGTT-clinic at 1 h vs OGTT-home at each 5-min interval from 60-90 min; Between OGTT-clinic at 2 h vs OGTT-home at each 5-min interval from 120-150 min	The correlation coefficient between the glucose levels of the OGTT at home vs at the clinic
The sensitivity and specificity, as well as the positive and negative predictive values of the OGTT at home vs the OGTT at the clinic	At 1 and 2 hours after the start of the OGTT	The sensitivity and specificity, as well as the positive and negative predictive values of pre-diabetes and diabetes of the OGTT-CGM with the highest correlation coefficient to the OGTT-CLI, at 1 and 2 hours after the start of the OGTT

Secondary Outcome Measures

Name	Time	Method
The sensitivity, specificity, positive and negative predictive value of the highest OGTT-home vs OGTT-clinic	Any of the values from 5-minute intervals 0-150 minutes of OGTT-home vs OGTT-clinic at 1 and 2 hours, respectively	The sensitivity, specificity, positive and negative predictive value of the highest glucose value form the OGTT at home vs the value of OGTT at the clinic at 1 and 2 hours, respectively
The sensitivity, specificity, positive and negative predictive value of the highest CGM value vs OGTT-clinic	Any of the values from 5-minute intervals days 1-14 of the CGM vs OGTT-clinic at 1 and 2 hours, respectively	The sensitivity, specificity, positive and negative predictive value of the highest glucose value form the CGM vs the value of OGTT at the clinic at 1 and 2 hours, respectively

Trial Locations

Locations (3)

Primary Health Care Center Bra Liv Rosenhälsan; 🇸🇪 Huskvarna, Jönköping County, Sweden

Primary Health Care Center Cityhälsan Centrum; 🇸🇪 Norrköping, Sweden

Primary Care Center Vårdcentralen Kärna; 🇸🇪 Linköping, Östergötland County, Sweden