Pre DiabeticCGMNCT07423065
The Impact of Continuous Glucose Monitoring on Glucose Variability and Weight Loss in Individuals With Prediabetes and Obesity
A study testing Continuous Glucose Monitoring (CGM) in people with Pre Diabetic and Obesity & Overweight, run by University of Primorska at 3 sites in Slovenia.
Trial summary
This randomized, crossover interventional study evaluates the effects of real-time (open) versus blinded continuous glucose monitoring (CGM) on glycemic variability, lifestyle behaviors, and metabolic outcomes in adults with prediabetes and overweight or obesity (BMI ≥ 27 kg/m²). Read more about this study
- Who is it for?
- Ages 18 to 70 years
- Conditions the study is for
- Pre Diabetic, Obesity & Overweight
- What is being tested?
- Continuous Glucose Monitoring (CGM)
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 34 participants
- Where
- 3 sitesSlovenia
- Study dates
- 15 Dec 2026to 1 Nov 2027
- Phase
- Interventional
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 70 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Adults aged 18-70 years.
- BMI ≥ 27 kg/m² (overweight or obese).
- Prediabetes, confirmed by:
- Impaired fasting glucose (IFG: 5.6-6.9 mmol/L), and/or Impaired glucose tolerance (IGT: 2-hour OGTT glucose 7.8-11.0 mmol/L).
- Stable body weight (±3 kg) in the last 3 months.
- No current use of antidiabetic or weight-loss medications.
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- Willingness and ability to wear a CGM device as instructed.
- Capacity to provide written informed consent.
- Recruitment from the Diabetes Outpatient Clinic, Community Health Center Koper (identified and invited from the clinic's database).
Who cannot join
- Diagnosis of type 1 or type 2 diabetes mellitus (fasting glucose ≥ 7.0 mmol/L or HbA1c ≥ 6.5%).
- Current or recent (within 3 months) use of:
- Any antidiabetic medication (insulin, metformin, GLP-1RA, SGLT2i, etc.), or anti-obesity pharmacotherapy.
- Pregnancy, breastfeeding, or planned pregnancy during the study period.
- Severe chronic disease that could influence glucose metabolism or study participation (e.g., chronic liver disease, renal failure, active malignancy).
- Endocrine disorders affecting metabolism (e.g., untreated thyroid disease, Cushing's syndrome).
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- Severe psychiatric illness or cognitive impairment limiting adherence or comprehension.
- Use of medications known to affect glucose metabolism (e.g., corticosteroids, atypical antipsychotics).
- Implanted electronic medical devices (e.g., pacemaker, defibrillator) that may interfere with CGM function.
- Known allergy or skin reaction to CGM adhesives or device materials.
- Participation in another interventional study within the previous 3 months.
Trial locations and contacts
3 sites in 1 country. Contact the study team or a site near you to ask about taking part.
Slovenia3 sites, 3 recruiting
- Recruiting
University of Primorska, Faculty of Health Sciences
Izola, 6310
Zala Jenko Pražnikar, PhD, zala.praznikar@upr.si
Ana Petelin, PhD
- Recruiting
Diabetes Outpatient Clinic, Community Health Center Koper, Slovenia
Koper, 6000
Ajda Urbas, MD, ajda.pipan@gmail.com
- Recruiting
Department Of endocrinology and diabetes, Medical Faculty, University of Ljubljana
Ljubljana, 1000
Mojca Jensterle Sever, PhD, mojcajensterle@yahoo.com
About this study
Official title: The Impact of Continuous Glucose Monitoring on Behavioral Change, Glucose Variability and Weight Loss in Individuals With Prediabetes and Obesity - a Randomized Crossover Study
This randomized, crossover interventional study evaluates the effects of real-time (open) versus blinded continuous glucose monitoring (CGM) on glycemic variability, lifestyle behaviors, and metabolic outcomes in adults with prediabetes and overweight or obesity (BMI ≥ 27 kg/m²). Thirty participants will undergo both open and blinded CGM phases, separated by a washout period. The study aims to assess whether access to real-time glucose data promotes behavioral change and improves metabolic health compared with blinded CGM use.
Read the detailed description
Prediabetes and obesity are major contributors to the development of type 2 diabetes and its complications. Early intervention focused on glycemic control and lifestyle modification is essential to prevent disease progression. Continuous glucose monitoring (CGM) provides real-time insight into glucose dynamics and may support behavioral change; however, evidence is limited on how access to glucose data influences sustained lifestyle modification and metabolic outcomes in individuals with prediabetes.
The primary objectives are to assess the impact of real-time (open) versus blinded CGM on (1) glycemic variability using sensitive dynamic metrics, and (2) behavioral changes, including dietary habits and physical activity, in adults with prediabetes and overweight or obesity.
Secondary objectives include evaluating the effects of CGM on anthropometric and metabolic parameters, biochemical and physiological markers of metabolic control, participant experience and acceptability of CGM, sustainability of lifestyle changes, and associations between glycemic variability and cardiometabolic risk reduction.
This prospective, randomized, open-label, blinded crossover interventional study will evaluate the effects of CGM on behavior, glycemic variability, and weight loss in adults with prediabetes and obesity (BMI ≥ 27 kg/m²). Thirty participants will be recruited from the Diabetes Outpatient Clinic of the Community Health Center Koper. After screening and a 10-day blinded CGM run-in period, participants will be randomized (1:1) to one of two sequences: (A) open CGM for 12 weeks followed by a 30-day washout and 12 weeks of blinded CGM, or (B) blinded CGM for 12 weeks followed by washout and 12 weeks of open CGM. Participants will attend baseline and follow-up visits for anthropometric, biochemical, and behavioral assessments during each study phase.
- Conditions
- Pre Diabetic, Obesity & Overweight
- Being tested
- Continuous Glucose Monitoring (CGM)
- Keywords
- continuous glucose monitoring, obesity, prediabetes, behavior
- Medical subject headings
- Glucose Intolerance, Obesity, Overweight, Prediabetic State, Behavior
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Continuous Glucose Monitoring (CGM)Device
Use of a continuous glucose monitoring system to measure interstitial glucose levels. During the open CGM phase, participants have real-time access to glucose data; during the blinded CGM phase, glucose data are masked from participants.
| Study group | Role | What they receive |
|---|---|---|
| Open CGM | Experimental | Not described Receives: Device: Continuous Glucose Monitoring (CGM) |
| Blinded CGM | Experimental | Not described Receives: Device: Continuous Glucose Monitoring (CGM) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Glycemic Variability Assessed by Coefficient of Variation from CGM
Change in glucose coefficient of variation (CV%), calculated from CGM data, comparing open versus blinded CGM phases. Unit of Measure: Percentage (%)
Measured: End of each 12-week CGM phase
Postprandial Glucose Excursions Measured by CGM
Mean postprandial glucose excursion (PPGE) following habitual meals, derived from CGM data. Unit of Measure: mmol/L
Measured: End of each 12-week CGM phase
Change in Mean Daily Energy Intake
Change in mean daily caloric intake assessed using participant-completed food diaries. Unit of Measure: kcal/day
Measured: End of each 12-week CGM phase
Secondary outcomes (11)
Change in Time in Tight Range (3.9-7.8 mmol/L) Measured by Continuous Glucose Monitoring
Change in percentage of time glucose values are within the tight range of 3.9-7.8 mmol/L, derived from continuous glucose monitoring (CGM) data, comparing open versus blinded CGM phases. Unit of Measure: Percentage (%)
Measured: End of each 12-week CGM phase
Change in Glycemic Variability Assessed by Standard Deviation from CGM
Change in standard deviation of interstitial glucose values derived from CGM data, comparing open versus blinded CGM phases. Unit of Measure: mmol/L
Measured: End of each 12-week CGM phase
Change in Continuous Overall Net Glycemic Action (CONGA) from CGM
Change in CONGA index calculated from CGM glucose profiles, reflecting short-term glycemic variability, comparing open versus blinded CGM phases. Unit of Measure: mmol/L
Measured: End of each 12-week CGM phase
Change in Glycemic Complexity Assessed by Entropy-Based Indices from CGM
Change in glucose pattern complexity assessed using entropy-based indices derived from CGM data, comparing open versus blinded CGM phases. Unit of Measure: Unitless index
Measured: End of each 12-week CGM phase
Postprandial Incremental Area Under the Curve (iAUC) Derived from CGM
Incremental area under the glucose curve (iAUC) following habitual meals, calculated from CGM data. Unit of Measure: mmol/L·min
Measured: End of each 12-week CGM phase
Adherence to Continuous Glucose Monitoring
Adherence to CGM use, defined as percentage of days with valid CGM data and frequency of data uploads. Unit of Measure: Percentage (%)
Measured: End of each 12-week CGM phase
Change in Fasting Plasma Glucose
Change in Fasting Plasma Glucose measured in mmol/L by biochemical analyzer.
Measured: Baseline; end of each 12-week CGM phase
Change in Body Weight
Change in Body Weight (in kg) from baseline to week twelve (of each CGM phase).
Measured: Baseline; end of each 12-week CGM phase
Change in Physical Activity Assessed by IPAQ Short Form
Physical activity assessed using the International Physical Activity Questionnaire (IPAQ) short form, reported as total MET-minutes per week.
Measured: Baseline; end of each 12-week CGM phase
Change in Health Status Assessed by EQ-VAS
Change in Health Status Assessed by EQ-VAS index score (0-100; higher scores indicate better perceived health).
Measured: Baseline; end of each 12-week CGM phase
Change in Glycated Hemoglobin (HbA1c)
Change in Glycated Hemoglobin (HbA1c) measured in % (according to The National Glycohemoglobin Standardization Program - NGSP)
Measured: Baseline; end of each 12-week CGM phase
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Feb 2026
- Study start15 Dec 2026 (estimated)
- Primary completion1 Sep 2027 (estimated)
- Study completion1 Nov 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Pre DiabeticStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Enrolment
- 34 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Primorska
- Sponsor type
- University, hospital or other
- Collaborators
- Diabetes Outpatient Clinic, Community Health Center Koper, Slovenia, University Medical Centre Ljubljana
- Responsible party
- Principal investigator, Zala Jenko Praznikar, University of Primorska
- Investigators
- Ajda Urbas, MD, Principal investigator, Diabetes Outpatient Clinic, Community Health Center Koper, SloveniaMojca Jensterle Sever, PhD, Study chair, University Medical Centre Ljubljana, Department Of endocrinology and diabetes, Medical Faculty, University of LjubljanaZala Jenko Pražnikar, PhD, Study chair, University of Primorska, Faculty of Health Sciences
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07423065
- Sponsor's protocol ID
- CGM
- Acronym
- CGM
- Status last verified
- Oct 2026
- First submitted
- 26 Jan 2026
- Last updated
- 22 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided