Continuous Glucose Monitors (CGM) for Type 2 Diabetes (T2D) Risk Evaluation

Study Overview
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Brief Summary
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The purpose of this research study is to determine whether continuous glucose monitors (CGM) are a safe, effective, and acceptable way to evaluate type 2 diabetes risk in youth as compared to the standard 2-hour oral glucose tolerance test (OGTT). This study will involve wearing a CGM, wearing a physical activity tracker, responding to surveys, and completing at-home glucose and mixed food challenge while wearing the CGM. Subjects will also be asked to complete an interview by phone or videoconference after wearing the CGM.

Detailed Description
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Youth-onset type 2 diabetes (T2D), an increasingly common and aggressive disease that disproportionately impacts racial and ethnic minorities, presents several diagnostic challenges. The rapid loss of glycemic control soon after T2D diagnosis makes early identification an important goal in pediatrics, and risk-based screening has been recommended for children for over two decades. However, the screening tests currently used in practice, including hemoglobin A1c (HbA1c), fasting glucose, and 2-hour oral glucose tolerance test (OGTT), have significant drawbacks. Real-time continuous glucose monitors (CGM) are promising new tools for risk stratification in individuals with dysglycemia. These patient-worn medical devices measure interstitial glucose every 5 minutes and offer glimpses into an individual's everyday life, which may include consumption of carbohydrates in amounts larger than that assessed in an OGTT, enhancing test sensitivity. Whether use of CGMs to evaluate type 2 diabetes risk in free-living youth is feasible and acceptable to patients and families is unknown. Assessment of CGM with standardized, but practical, home-based glucose and mixed-meal challenges is needed to determine facilitators and barriers to use of this technology-driven approach in clinical practice. Without advancement in the approach to screening for youth-onset T2D, there is ongoing risk of failure to understand which individuals are at highest risk for complications and could benefit the most from intervention early in the disease process. In this single-arm prospective study, participants will attend one in-person study visit to complete 2-hour oral glucose tolerance test after overnight fast. Participants will wear a continuous glucose monitor and a wrist-worn actigraphy device for physical activity and sleep measurement for 10 days beginning on the day of the study visit, then return the monitors by mail. During the 10 day wear period, participants will respond to text message-based surveys to document food intake, physical activity, and sleep times and will complete two at-home challenges: 1) glucose challenge using study-provided glucose beverage that is identical to that they consume during clinical oral glucose tolerance test; and 2) food challenge with mixed carbohydrate/fat/protein-containing food of their choice. Glucose trends during these at-home challenges will be compared with oral glucose tolerance test obtained during the study visit. Individual interviews will be conducted upon completion of CGM wear to assess acceptability of the use of at-home glucose challenge and CGM wear as a strategy to evaluate diabetes risk in youth.

Official Title
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Feasibility and Acceptability of Home Use Continuous Glucose Monitors for Type 2 Diabetes Risk Evaluation in Youth

Conditions
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Overweight and Obesity, PreDiabetes, Insulin Resistance

Intervention / Treatment
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* Device: CGM


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Any gender, age 8-18 years Tanner 2 or higher pubertal development Overweight or obese (BMI ≥85th percentile for age/sex, or ≥ 25 kg/m2 for participants =18 years) A) No previously documented abnormal HbA1c or glucose but at higher risk for T2D based on race/ethnicity (Black, Hispanic, Asian, Native American, Pacific Islander), diagnosis with dyslipidemia, hypertension, polycystic ovary syndrome, presence of acanthosis nigricans, or first degree relative with T2D; or B) previously documented (within 6 months) HbA1c 5.7-7.0%, fasting glucose ≥100 mg/dL, or 2-hour plasma glucose on OGTT of ≥140 mg/dL Consent (adult subjects), parental/guardian permission (if applicable), assent (if applicable) Willingness to wear ActiGraph watch and CGM continuously for 10 day study duration Exclusion Criteria: Current or recent (within 1 month) use of diabetes-related medication Current use of hydroxyurea (due to interference with CGM) Known type 1, cystic fibrosis-related, or medication-induced diabetes Potential subject unable to speak or read in English Severe cognitive impairment Current or previous pregnancy

Ages Eligible for Study
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Minimum Age: 8 Years
Maximum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Intervention Model: Single Group Assignment
Interventional Model Description: Subjects will wear a continuous glucose monitor (CGM) to determine the feasibility and acceptability of the device to evaluate risk of youth developing Type 2 Diabetes (T2D).
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: CGM use for T2D risk evaluation<br>All participants will complete a standard 2-hour oral glucose tolerance test (OGTT), wear a CGM for 10 days, complete at-home glucose challenge, and provide qualitative feedback about their experiences with both OGTT and CGM use for risk evaluation. | Device: CGM<br>* Participants will wear blinded Dexcom G6 Pro continuously for 10 days in their home environment. Two challenges will be completed at home: 1) glucose, using 1.75 g/kg (max 75g) glucose beverage provided by study team, and 2) mixed food, containing 50g carb as well as protein and fat content of participant's choice.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Feasibility of CGM use to determine Type 2 Diabetes Risk | Completeness of CGM data (≥ 80% of days with data) | 10 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sensitivity of at-home CGM-measured glucose challenge | Sensitivity of CGM-glucose 2 hours after at-home glucose beverage ingestion to predict OGTT-2h≥140 mg/dL | 2 Hours | 
| Specificity of at-home CGM-measured glucose challenge | Specificity of CGM-glucose 2 hours after at-home glucose beverage ingestion to predict OGTT-2h≥140 mg/dL | 2 Hours | 
| Positive predictive value of at-home, CGM-measured glucose challenge | Positive predictive value of CGM-glucose 2 hours after at-home glucose beverage ingestion to predict OGTT-2h≥140 mg/dL | 2 Hours | 
| Negative predictive value of at-home, CGM-measured glucose challenge | Negative predictive value of CGM-glucose 2 hours after at-home glucose beverage ingestion to predict OGTT-2h≥140 mg/dL | 2 Hours | 
| Acceptability of CGM use for at-home T2D risk evaluation in youth | Interview-based | 30 minutes |