CGM Plus GEM in Prediabetes (IMPEDE)

Libre 2 CGM Plus Glycemic Excursion mIniMization (GEM) in the Treatment of PrEDiabEtes

This study is designed to look into the effect of a lifestyle management guide called GEM (Glycemic Excursion Minimization) alongside continuous glucose monitoring (CGM) and an activity monitor (FitBit) and the effect this can have on persons with prediabetes.

Study Overview

• Status: Completed
• Conditions: PreDiabetes
• Intervention / Treatment: Behavioral: GEM; Other: Routine Care

Detailed Description

For people with prediabetes, it may be possible to delay or prevent the progression to diabetes by reducing postprandial glucose (PPG). The Glycemic Excursion Minimization (GEM) lifestyle intervention guide can reduce PPG in people with type 2 diabetes and has been studied in this population with continuous glucose monitor (CGM) feedback to help the user learn what elevates and lowers their PPG. This study examines if the GEM lifestyle intervention guide plus continuous feedback from the FreeStyle Libre 2 CGM and FitBit will allow participants with prediabetes with HbA1c 6.0-6.4% to (1) improve their metabolic status by illustrating the effects of their routine food and physical activity choices on their glucose levels and variability, more than Routine Care (RC), and (2) to enhance these investigations by adding comprehensive plasma proteomics to the analyses. The investigators will recruit up to 36 adult participants with prediabetes through the University of Colorado, with the goal of having at least 30 participants complete the study. Participants will be randomized to the intervention or RC. Those randomized to the intervention will be given a GEM treatment manual, Libre2 CGM, and an activity monitor and will follow the GEM lifestyle intervention guide for 4 months. Those participants randomized to RC will follow recommendations from their primary care provider. RC participants will have the opportunity to receive GEM four months after consenting and completing the RC pre-post assessments if they meet eligibility criteria. It is anticipated that 50% of the RC participants will want/be able to cross over to GEM upon completion of RC. Pre-post blinded CGM data and activity data, clinical, and psychosocial outcomes will be collected and analyzed. It is anticipated that this pilot project will demonstrate the benefits of using GEM plus FreeStyle Libre 2 and FitBit to reduce percentage of CGM readings >120 mg/dL, from blinded pre-post FreeStyle Libre Pro, as well as reduce BMI and depressive symptoms and increase modified diabetes empowerment. Comprehensive proteomics will be measured on small samples of EDTA treated venous blood. Individual proteins and protein pathways will be measured for each of the participants.

• Study Type: Interventional
• Enrollment (Actual): 61
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Colorado
    • Aurora, Colorado, United States, 80045
      • University of Colorado- Anschutz Medical Campus

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 21 years to 66 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age 25-70 years
• A1C 6.0-6.4
• Documented diagnosis of prediabetes
• Have a smart phone
• Able to read English, as the GEM guide is currently only available in English
• Willing and able to follow the study procedures as instructed

Exclusion Criteria:

• Diagnosis of diabetes mellitus
• Currently taking any diabetes medication
• Currently taking medication that promotes insulin resistance or otherwise interferes with metabolic control (e.g., prednisone)
• Has a condition that precludes a low carbohydrate diet, such as gastroparesis
• Has a physical or medical condition that precludes walking 120 steps per minute for 10 minutes or longer
• Has documented kidney disease that would preclude participation in study per PI discretion
• Active or planned cancer treatment
• Extreme visual or hearing impairment that would impair ability to use real-time CGM
• Pregnant or anticipates becoming pregnant in the next 4 months
• Anticipates moving within the next 4 months
• Treating physician, for any reason, considers their patient inappropriate for the study (e.g., uncontrolled bipolar disease)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: GEM + CGM + Activity Monitor; GEM plus CGM and Activity Monitor (FitBit)	Behavioral: GEM; The intervention group will be given Libre 2 supplies for 4 months, an activity monitor, and the 4-chapter GEM paper guide. The intervention group will complete a virtual or inperson study visit where they will receive instructions on how to apply their unblinded Freestyle Libre and connect it to the study account, as well as how to register their Fitbit to the study account. Participants will receive one telephone call to review use of the GEM Guide and call at two weeks and six weeks later when the probability of dropouts from lifestyle intervention peaks. Participants will follow the self-directed GEM guide for 4 months (a 1-month treatment period followed by a 3-month maintenance period) while wearing a FitBit activity monitor and a Freestyle Libre 2 CGM.
Active Comparator: Routine Care; Usual care already being received for prediabetes as treated by their care team.	Other: Routine Care; Participant's current prediabetes treatment.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Percentage of CGM Glucose Readings > 120 mg/dL	Change in percentage of CGM glucose readings > 120 mg/dL from pre-intervention (baseline) blinded CGM to post-intervention (4.5 months) blinded CGM.	Pre-Intervention (Baseline) to post Intervention (4.5 Months)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in HbA1c	Change in HbA1c from pre-intervention (baseline) to post-intervention (4.5 months).	Pre-Intervention (Baseline) to post Intervention (4.5 Months)
Change in Glucose Variability	Change in glucose variability (GV%) as measured by CGM, from pre-intervention (baseline) to post-intervention (4.5 months). Glucose variability was measured by CGM metrics coefficient of variation (%CV) and Standard Deviation (SD).	Pre-Intervention (Baseline) to post Intervention (4.5 Months)
Change in Body Mass Index	Change in Body Mass Index (BMI) from pre-intervention (baseline) to post-intervention (4.5 months).	Pre-Intervention (Baseline) to post Intervention (4.5 Months)
Change in Cardiovascular Risk	Change in cardiovascular risk as calculated by a validated risk calculator from pre-intervention (baseline) to post-intervention (4.5 months). The ASCVD Risk Estimator Plus was used to calculate cardiovascular risk. It provides a percentage score that estimates 10-year risk of having a heart attack or stroke. Low risk <5%, Borderline (5%-7.4%) Intermediate (7.5%-19.9%) High (> 20%).	Pre-Intervention (Baseline) to post Intervention (4.5 Months)
Change in Empowerment	Change in empowerment as measured by modified Diabetes Empowerment Scale-Short Form, from pre-intervention (baseline) to post-intervention (4.5 months). The Diabetes Empowerment Scale-Short Form measures the psychosocial self-efficacy of people with diabetes. An item checked "strongly agree" receives 5 points; "agree" - 4 points; "neutral" - 3 points; "disagree" - 2 points; and "strongly disagree" receives 1 point. All items are summed, "Low" = 8-20, "Moderate" = 21-30, "High" = 31-40. Possible scores on the scale ranges from 8-40.	Pre-Intervention (Baseline) to post Intervention (4.5 Months)
Change in Depressive Symptoms	Change in depression score as measured by PHQ-8 at pre-intervention (baseline) and post-intervention (4.5 months). The Patient Health Questionnaire-8 is a self-report screening tool for depression. Each item scores 0 (not at all) to 3 (nearly every day). Total scores range from 0 to 24, with higher scores indicating greater depression severity.	Pre-Intervention (Baseline) to post Intervention (4.5 Months)
Change in Diabetes Knowledge	Change in diabetes knowledge as measured by a modified Diabetes Knowledge Scale from pre-intervention (baseline) to post-intervention (4.5 months). The Diabetes Knowledge Scale is a valid measure containing 30 questions for assessing diabetes knowledge. The items are scored as correct or incorrect, and the correct items were summed to obtain a total score. Scores range from 0 to 30, with higher scores indicating greater knowledge.	Pre-Intervention (Baseline) to post Intervention (4.5 Months)
Dietary Habits	Change in dietary habits as measured by Carbohydrate Routine Consumption Scale (CRC) from pre-intervention (baseline) to post-intervention (4.5 months). The CRC measures carb intake, focusing on how much and what kind (high vs. low glycemic impact), rather than daily total grams. Scoring involves evaluating foods on a 4 or 5-point scale based on nutrients like fiber, free sugars, sodium, and potassium, guiding better choices by highlighting healthier options within carb categories, with higher scores indicating better quality. The CRC score is the sum of the number of servings of 16 different high-carb food classes eaten (e.g., dried fruits) in an average week. There are no subscales. Scale minimum is 0 (zero consumption of high-carb food foods). There is no scale maximum (people may eat as many servings of high glycemic load foods as they like). The CRC is not a comprehensive nutritional analysis. https://diabetesjournals.org/diabetes/article/68/Supplement_1/806-P/58163	Pre-Intervention (Baseline) to post Intervention (4.5 Months)
Motivation and Attitudes Toward Changing Health	Change in Motivation and Attitudes Toward Changing Health (MATCH) score from pre-intervention (baseline) to post-intervention (4.5 months). The Motivation and Attitudes Toward Changing Health (MATCH) is a 9-item scale that provides a profile of factors influencing motivation. Patients rate their agreement on a 5-point scale (1=Strongly Disagree, 5=Strongly Agree). An average of all items or subscales provides an overall score/motivational profile. Higher Scores (closer to 5) indicate stronger motivation, ability, and belief in the value of change, while lower Scores (closer to 1) suggest potential barriers, such as ambivalence, perceived lack of control, or feeling changes aren't impactful.	Pre-Intervention (Baseline) to post Intervention (4.5 Months)

Collaborators and Investigators

• Sponsor: University of Colorado, Denver
• Collaborators: University of Virginia; Abbott Diabetes Care
• Investigators: Principal Investigator: Tamara Oser, MD, Associate Professor, Dept. Family Medicine

Study record dates

Study Major Dates

• Study Start (Actual): November 1, 2022
• Primary Completion (Actual): January 15, 2025
• Study Completion (Actual): January 15, 2025

Study Registration Dates

• First Submitted: October 6, 2022
• First Submitted That Met QC Criteria: October 12, 2022
• First Posted (Actual): October 14, 2022

Study Record Updates

• Last Update Posted (Actual): June 3, 2026
• Last Update Submitted That Met QC Criteria: June 1, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: prevention; continuous glucose monitor; prediabetes; lifestyle guide
• Additional Relevant MeSH Terms: Endocrine System Diseases; Metabolic Diseases; Glucose Metabolism Disorders; Diabetes Mellitus; Nutritional and Metabolic Diseases; Prediabetic State
• Other Study ID Numbers: 21-4931

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No