Real-time glucose monitoring to reduce glucose swings and support weight loss in people with prediabetes and obesity

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 project tests whether wearing a real-time continuous glucose monitor helps adults with prediabetes and BMI ≥27 reduce glucose swings and lose weight compared with wearing a blinded monitor.

Quick facts

• Phase: Not applicable
• Study type: Interventional
• Enrollment: 34 (estimated)
• Ages: 18 Years to 70 Years
• Sex: All
• Sponsor: University of Primorska (Academic / other)
• Locations: 3 sites (Izola and 2 other locations)
• Trial ID: NCT07423065 on ClinicalTrials.gov

What this trial studies

This randomized, open-label, blinded-crossover interventional study enrolls 30 adults with prediabetes and BMI ≥27 kg/m² and compares periods of real-time (open) versus blinded continuous glucose monitoring (CGM). Participants complete a 10-day blinded CGM run-in and then undergo both open and blinded CGM phases separated by a washout period, with order randomized. Outcomes include glycemic variability using dynamic metrics, changes in diet and physical activity, anthropometric and metabolic markers, and participant experience with CGM. The goal is to see whether access to real-time glucose data drives sustainable behavioral change and improves metabolic health versus blinded monitoring.

Who should consider this trial

Good fit: Adults aged 18–70 with confirmed prediabetes, BMI ≥27 kg/m², stable recent weight, not using antidiabetic or weight-loss medications, and able to wear a CGM and attend the clinic in Slovenia.

Not a fit: People with diagnosed type 1 or type 2 diabetes, those using antidiabetic or anti-obesity medications, pregnant or breastfeeding individuals, or those with severe chronic illnesses or inability to wear a CGM are unlikely to benefit from this protocol.

Why it matters

Potential benefit: If successful, this approach could help people with prediabetes better understand their glucose responses, change daily habits, reduce glucose variability, and achieve modest weight loss.

How similar studies have performed: Previous studies in people with diabetes show CGM often changes behavior and improves glucose metrics, while evidence in prediabetes is limited but emerging with mixed results.

Eligibility criteria

Inclusion Criteria:

* 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.
* 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).

Exclusion Criteria:

* 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).
* 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.

Where this trial is running

Izola and 2 other locations

• University of Primorska, Faculty of Health Sciences — Izola, Slovenia (Recruiting)
• Diabetes Outpatient Clinic, Community Health Center Koper, Slovenia — Koper, Slovenia (Recruiting)
• Department Of endocrinology and diabetes, Medical Faculty, University of Ljubljana — Ljubljana, Slovenia (Recruiting)

Study contacts

• Principal investigator: Ajda Urbas, MD — Diabetes Outpatient Clinic, Community Health Center Koper, Slovenia
• Study coordinator: Ajda Urbas, medical doctor

Conditions Pre Diabetic; Obesity & Overweight; continuous glucose monitoring; obesity; prediabetes; behavior