Obesity & Overweight, Pre Diabetic
Conditions
Keywords
continuous glucose monitoring, obesity, prediabetes, behavior
Brief 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). 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.
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.
Interventions
DEVICEContinuous Glucose Monitoring (CGM)
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.
Sponsors
University of Primorska
Diabetes Outpatient Clinic, Community Health Center Koper, Slovenia
University Medical Centre Ljubljana
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
PREVENTION
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 70 Years
Healthy volunteers
No
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Glycemic Variability Assessed by Coefficient of Variation from CGM | End of each 12-week CGM phase | Change in glucose coefficient of variation (CV%), calculated from CGM data, comparing open versus blinded CGM phases. Unit of Measure: Percentage (%) |
| Postprandial Glucose Excursions Measured by CGM | End of each 12-week CGM phase | Mean postprandial glucose excursion (PPGE) following habitual meals, derived from CGM data. Unit of Measure: mmol/L |
| Change in Mean Daily Energy Intake | End of each 12-week CGM phase | Change in mean daily caloric intake assessed using participant-completed food diaries. Unit of Measure: kcal/day |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in Time in Tight Range (3.9-7.8 mmol/L) Measured by Continuous Glucose Monitoring | End of each 12-week CGM phase | 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 (%) |
| Change in Glycemic Variability Assessed by Standard Deviation from CGM | End of each 12-week CGM phase | Change in standard deviation of interstitial glucose values derived from CGM data, comparing open versus blinded CGM phases. Unit of Measure: mmol/L |
| Change in Continuous Overall Net Glycemic Action (CONGA) from CGM | End of each 12-week CGM phase | 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 |
| Change in Glycemic Complexity Assessed by Entropy-Based Indices from CGM | End of each 12-week CGM phase | 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 |
| Postprandial Incremental Area Under the Curve (iAUC) Derived from CGM | End of each 12-week CGM phase | Incremental area under the glucose curve (iAUC) following habitual meals, calculated from CGM data. Unit of Measure: mmol/L·min |
| Adherence to Continuous Glucose Monitoring | End of each 12-week CGM phase | Adherence to CGM use, defined as percentage of days with valid CGM data and frequency of data uploads. Unit of Measure: Percentage (%) |
| Change in Fasting Plasma Glucose | Baseline; end of each 12-week CGM phase | Change in Fasting Plasma Glucose measured in mmol/L by biochemical analyzer. |
| Change in Body Weight | Baseline; end of each 12-week CGM phase | Change in Body Weight (in kg) from baseline to week twelve (of each CGM phase). |
| Change in Physical Activity Assessed by IPAQ Short Form | Baseline; end of each 12-week CGM phase | Physical activity assessed using the International Physical Activity Questionnaire (IPAQ) short form, reported as total MET-minutes per week. |
| Change in Health Status Assessed by EQ-VAS | Baseline; end of each 12-week CGM phase | Change in Health Status Assessed by EQ-VAS index score (0-100; higher scores indicate better perceived health). |
| Change in Glycated Hemoglobin (HbA1c) | Baseline; end of each 12-week CGM phase | Change in Glycated Hemoglobin (HbA1c) measured in % (according to The National Glycohemoglobin Standardization Program - NGSP) |
Countries
Slovenia
Contacts
CONTACTAjda Urbas, medical doctor
PRINCIPAL_INVESTIGATORAjda Urbas, MD
Diabetes Outpatient Clinic, Community Health Center Koper, Slovenia
STUDY_CHAIRMojca Jensterle Sever, PhD
University Medical Centre Ljubljana, Department Of endocrinology and diabetes, Medical Faculty, University of Ljubljana
STUDY_CHAIRZala Jenko Pražnikar, PhD
University of Primorska, Faculty of Health Sciences
Outcome results
None listed