An interventional study of GEM and Routine Care in PreDiabetes, sponsored by University of Colorado, Denver. Completed at 1 site in United States. Open to participants aged 25 Years to 70 Years. Per ClinicalTrials.gov, last updated 2026-06-03.
Sponsored by University of Colorado, Denver · Not applicable, Interventional, and Prevention
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.
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.
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Exclusion Criteria:
GEM plus CGM and Activity Monitor (FitBit)
Behavioral: GEM
Usual care already being received for prediabetes as treated by their care team.
Other: Routine Care
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.
Participant's current prediabetes treatment.
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.
Time frame: Pre-Intervention (Baseline) to post Intervention (4.5 Months)
Change in HbA1c
Change in HbA1c from pre-intervention (baseline) to post-intervention (4.5 months).
Time frame: 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).
Time frame: 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).
Time frame: 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%).
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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
Time frame: 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.
Time frame: Pre-Intervention (Baseline) to post Intervention (4.5 Months)
| Milestone | GEM + CGM + Activity Monitor Only (4.5 Months). | Routine Care First (4.5 Months), Then GEM + CGM + Activity Monitor (4.5 Months) |
|---|---|---|
| Started | 14 | 21 |
| Completed | 12 | 21 |
| Not completed | 2 | 0 |
Change in percentage of CGM glucose readings \> 120 mg/dL from pre-intervention (baseline) blinded CGM to post-intervention (4.5 months) blinded CGM.
| percentage of CGM readings | GEM + CGM + Activity Monitor | Routine Care |
|---|---|---|
| Pre Intervention | 25.0 ± 18.3 | 21.5 ± 18.1 |
| Post Intervention | 16.9 ± 18.4 | 21.7 ± 18.3 |
Change in HbA1c from pre-intervention (baseline) to post-intervention (4.5 months).
| Percent (%) HbA1c | GEM + CGM + Activity Monitor | Routine Care |
|---|---|---|
| Pre Intervention | 6.2 ± 0.1 | 6.2 ± 0.2 |
| Post Intervention | 6.0 ± 0.3 | 6.1 ± 0.2 |
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).
| Percent (%) Glucose Variability | GEM + CGM + Activity Monitor | Routine Care |
|---|---|---|
| Pre Intervention | 18.6 ± 4.3 | 18.4 ± 4.3 |
| Post Intervention | 16.6 ± 3.5 | 19.2 ± 4.9 |
Change in Body Mass Index (BMI) from pre-intervention (baseline) to post-intervention (4.5 months).
| kilograms per meter squared (kg/m²) | GEM + CGM + Activity Monitor | Routine Care |
|---|---|---|
| Pre Intervention | 30.7 ± 6.6 | 30.8 ± 8.0 |
| Post Intervention | 29.2 ± 6.6 | 30.3 ± 7.7 |
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%).
| Percent (%) | GEM + CGM + Activity Monitor | Routine Care |
|---|---|---|
| Pre Intervention | 5.6 ± 4.5 | 5.2 ± 3.6 |
| Post Intervention | 6.0 ± 4.8 | 5.1 ± 4.0 |
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.
| scores on a scale | GEM + CGM + Activity Monitor | Routine Care |
|---|---|---|
| Pre Intervention | 32.8 ± 5.3 | 30.4 ± 6.9 |
| Post Intervention | 36.6 ± 5.6 | 32.8 ± 5 |
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.
| scores on a scale | GEM + CGM + Activity Monitor | Routine Care |
|---|---|---|
| Pre Intervention | 2.6 ± 2.3 | 3.5 ± 2.5 |
| Post Intervention | 2.0 ± 2.1 | 3.2 ± 3.1 |
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.
| Percent (%) Correct | GEM + CGM + Activity Monitor | Routine Care |
|---|---|---|
| Pre Intervention | 61.9 ± 8.1 | 62.8 ± 9.5 |
| Post Intervention | 74.5 ± 7.2 | 62.8 ± 8.6 |
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
| scores on a scale | GEM + CGM + Activity Monitor | Routine Care |
|---|---|---|
| Pre Intervention | 32.5 ± 19.8 | 29.4 ± 18.2 |
| Post Intervention | 18.8 ± 20.3 | 33.8 ± 25.3 |
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.
| scores on a scale | GEM + CGM + Activity Monitor | Routine Care |
|---|---|---|
| Pre Intervention | 4.58 ± 0.4 | 4.57 ± 0.37 |
| Post Intervention | 4.57 ± 0.41 | 4.63 ± 0.44 |
Collected over From enrollment until end of RCT, up to 4.5 months for the intervention group (RC + GEM + Fitbit) and up to 9 months for the RC cross-over group.. Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| GEM + CGM + Activity Monitor | 0/29 (0%) | 2/29 (6.9%) | 5/29 (17.2%) |
| Routine Care | 0/21 (0%) | 0/21 (0%) | 0/21 (0%) |
| Routine Care - Between Arms | 0/15 (0%) | 0/15 (0%) | 1/15 (6.7%) |
| Event | GEM + CGM + Activity Monitor | Routine Care | Routine Care - Between Arms |
|---|---|---|---|
| DiverticulitisGastrointestinal disorders | 1/29 | 0/21 | 0/15 |
| Pulmonary EmbolismRespiratory, thoracic and mediastinal disorders | 1/29 | 0/21 | 0/15 |
| Event | GEM + CGM + Activity Monitor | Routine Care | Routine Care - Between Arms |
|---|---|---|---|
| Torn ACLMusculoskeletal and connective tissue disorders | 0/29 | 0/21 | 1/15 |
| Hip replacementSurgical and medical procedures | 1/29 | 0/21 | 0/15 |
| Chondrocalcinosis (pseudo gout)Musculoskeletal and connective tissue disorders | 1/29 | 0/21 | 0/15 |
| Knee injuryMusculoskeletal and connective tissue disorders | 1/29 | 0/21 | 0/15 |
| Surgical repair (right hip)Surgical and medical procedures | 1/29 | 0/21 | 0/15 |
| Back PainMusculoskeletal and connective tissue disorders | 1/29 | 0/21 | 0/15 |
Baseline demographic information for participants who completed "GEM + CGM + Activity Monitor Only" and "Routine Care First, then GEM + CGM + Activity Monitor" arms.
| Age, Continuous(Years) | GEM + CGM + Activity Monitor Only (4.5 Months). | Routine Care First (4.5 Months), Then GEM + CGM + Activity Monitor (4.5 Months) | Total |
|---|---|---|---|
| Mean | 58.7 ± 11.9 | 58.6 ± 10.3 | 58.6 ± 10.8 |
| Sex: Female, Male(Participants) | GEM + CGM + Activity Monitor Only (4.5 Months). | Routine Care First (4.5 Months), Then GEM + CGM + Activity Monitor (4.5 Months) | Total |
|---|---|---|---|
| Female | 12 | 17 | 29 |
| Male | 2 | 4 | 6 |
| Race (NIH/OMB)(Participants) | GEM + CGM + Activity Monitor Only (4.5 Months). | Routine Care First (4.5 Months), Then GEM + CGM + Activity Monitor (4.5 Months) | Total |
|---|---|---|---|
| American Indian or Alaska Native | 0 | 0 | 0 |
| Asian | 0 | 2 | 2 |
| Native Hawaiian or Other Pacific Islander | 0 | 0 | 0 |
| Black or African American | 1 | 0 | 1 |
| White | 12 | 19 | 31 |
| More than one race | 1 | 0 | 1 |
| Unknown or Not Reported | 0 | 0 | 0 |
| Ethnicity (NIH/OMB)(Participants) | GEM + CGM + Activity Monitor Only (4.5 Months). | Routine Care First (4.5 Months), Then GEM + CGM + Activity Monitor (4.5 Months) | Total |
|---|---|---|---|
| Hispanic or Latino | 4 | 1 | 5 |
| Not Hispanic or Latino | 10 | 20 | 30 |
| Unknown or Not Reported | 0 | 0 | 0 |
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University of Colorado, Denver