Reproducibility of Continuous Glucose Monitoring (CGM) in the Assessment of Glucose Metabolism Disorders in Children With Cystic Fibrosis (CGMUCODIAB)

Glucose metabolism disorders in cystic fibrosis (CF-GMD) are common and have a negative clinical impact. Screening currently relies on the oral glucose tolerance test (OGTT); however, this procedure is burdensome and complex for both patients and healthcare providers. Continuous glucose monitoring (CGM) is increasingly used in CF centers for CF-GMD screening, either alone or alongside the OGTT. While long-term (one-year) OGTT reproducibility is known to be poor, the short- and medium-term reproducibility of CGM remains unknown. This examination is poised to become a major tool in CF-GMD investigation, upon which critical therapeutic decisions could be based. The primary objective of this project is to evaluate the short-term variability of CGM data.

Study Overview

• Status: Not yet recruiting
• Conditions: Glucose Metabolism Disorders in Cystic Fibrosis
• Intervention / Treatment: Device: Continuous Glucose Monitoring; Other: Eating Habits Questionnaire; Other: Use of an actigraphy watch

• Study Type: Interventional
• Enrollment (Estimated): 30
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Kévin PERGE, Dr; Phone Number: +33 04 72 11 88 90; Email: kevin.perge@chu-lyon.fr
• Study Contact Backup: Name: Philippe REIX, Prof; Phone Number: +33 04 27 85 54 70; Email: philippe.reix@chu-lyon.fr

Study Locations

• France
  • Bron, France, 69677
    • Hôpital Femme Mère Enfant (HFME)
    • Contact: Philippe REIX, Prof; Phone Number: +33 04 27 85 54 70; Email: philippe.reix@chu-lyon.fr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 10 years to 17 years (Child)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Patients aged 10 to 17 years
• Diagnosed with cystic fibrosis (CF)
• Managed by the pediatric CF care center (CRCM) of the Groupement Hospitalier Est
• Patients presenting with one of the following three stages are included: normal glucose tolerance with or without indeterminate glucose tolerance (INDET), impaired fasting glucose (IFG), and impaired glucose tolerance (IGT)

Exclusion Criteria:

• Patients with treated or untreated diabetes
• Patients presenting with a pulmonary exacerbation and currently receiving antibiotic therapy
• Patients participating in another clinical trial that could interfere, in the investigator's judgment, with the study findings
• Refusal of the patient and/or the legal guardian(s) to participate in the study
• Pregnant, parturient, or breastfeeding women
• Persons deprived of liberty by a judicial or administrative decision
• Persons undergoing psychiatric care
• Persons admitted to a healthcare or social institution for purposes other than research
• Persons not affiliated with a social security scheme or beneficiaries of a similar scheme

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Non-diabetic patient with cystic fibrosis; Children aged 10 to 17 years diagnosed with cystic fibrosis (CF). Patients presenting with one of the following three stages are included: normal glucose tolerance with or without indeterminate glucose tolerance (INDET), impaired fasting glucose (IFG), and impaired glucose tolerance (IGT). Patients will be equipped with a continuous glucose monitoring (CGM) sensor (Dexcom ONE+).

Device: Continuous Glucose Monitoring; Upon enrollment, patients will be equipped with a continuous glucose monitoring (CGM) sensor (Dexcom ONE+). Sensors will be placed on the posterior aspect of the dominant arm at M0, M3, and M6, and additionally on the non-dominant arm at M0 only, in order to evaluate site-dependent variability. At each time point, the sensors will be worn for 7 days to record various CGM parameters, including glycemic variability (analyzed between M0-M3 and M0-M6).; Other: Eating Habits Questionnaire; A 7-day dietary diary will be completed at M0, M3, and M6.; Other: Use of an actigraphy watch; Participants will wear an actigraphy watch during 7 days at M0, M3 and M6

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The variability of the "time in range" (%) parameter (70-140 mg/dL) between M0 and M3.	The variability of the "time in range" (%) parameter (70-140 mg/dL) between M0 and M3.	From enrollment to 3 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The variability of other CGM parameters between M0 and M3: percentage of time in hypoglycemia (<70 mg/dL)	The variability of other CGM parameters between M0 and M3: percentage of time in hypoglycemia (<70 mg/dL)	From enrollment to 3 months
The variability of other CGM parameters between M0 and M3: percentage of time in hyperglycemia (>140 mg/dL)	The variability of other CGM parameters between M0 and M3: percentage of time in hyperglycemia (>140 mg/dL)	From enrollment to 3 months
The variability of other CGM parameters between M0 and M3: glycemic variability (%)	The variability of other CGM parameters between M0 and M3: glycemic variability (%)	From enrollment to 3 months
The variability of other CGM parameters between M0 and M3: mean glucose level (mg/dL)	The variability of other CGM parameters between M0 and M3: mean glucose level (mg/dL)	From enrollment to 3 months
The variability of other CGM parameters between M0 and M3: number of glucose excursions >200 mg/dL	The variability of other CGM parameters between M0 and M3: number of glucose excursions >200 mg/dL	From enrollment to 3 months
The variability of other CGM parameters between M0 and M3: estimated HbA1c (eA1c)	The variability of other CGM parameters between M0 and M3: estimated HbA1c (eA1c)	From enrollment to 3 months
The variability of CGM parameters between M0 and M6: "time in range" (%) (70-140 mg/dL)	The variability of CGM parameters between M0 and M6: "time in range" (%) (70-140 mg/dL)	From enrollment to 6 months
The variability of CGM parameters between M0 and M6: percentage of time in hypoglycemia (<70 mg/dL),	The variability of CGM parameters between M0 and M6: percentage of time in hypoglycemia (<70 mg/dL),	From enrollment to 6 months
The variability of CGM parameters between M0 and M6: percentage of time in hyperglycemia (>140 mg/dL),	The variability of CGM parameters between M0 and M6: percentage of time in hyperglycemia (>140 mg/dL),	From enrollment to 6 months
The variability of CGM parameters between M0 and M6: glycemic variability (%),	The variability of CGM parameters between M0 and M6: glycemic variability (%),	From enrollment to 6 months
The variability of CGM parameters between M0 and M6: mean glucose level (mg/dL),	The variability of CGM parameters between M0 and M6: mean glucose level (mg/dL),	From enrollment to 6 months
The variability of CGM parameters between M0 and M6: number of glucose excursions >200 mg/dL	The variability of CGM parameters between M0 and M6: number of glucose excursions >200 mg/dL	From enrollment to 6 months
The variability of CGM parameters between M0 and M6: estimated HbA1c (eA1c)	The variability of CGM parameters between M0 and M6: estimated HbA1c (eA1c)	From enrollment to 6 months
The variability of CGM parameters according to the sensor placement site between M0 and M3 (inter-arm variability): "time in range" (%) (70-140 mg/dL)	The variability of CGM parameters according to the sensor placement site between M0 and M3 (inter-arm variability): "time in range" (%) (70-140 mg/dL)	From enrollment to 3 months
The variability of CGM parameters according to the sensor placement site between M0 and M3 (inter-arm variability): percentage of time in hypoglycemia (<70 mg/dL),	The variability of CGM parameters according to the sensor placement site between M0 and M3 (inter-arm variability): percentage of time in hypoglycemia (<70 mg/dL),	From enrollment to 3 months
The variability of CGM parameters according to the sensor placement site between M0 and M3 (inter-arm variability): percentage of time in hyperglycemia (>180 mg/dL)	The variability of CGM parameters according to the sensor placement site between M0 and M3 (inter-arm variability): percentage of time in hyperglycemia (>180 mg/dL)	From enrollment to 3 months
The variability of CGM parameters according to the sensor placement site between M0 and M3 (inter-arm variability): glycemic variability (%)	The variability of CGM parameters according to the sensor placement site between M0 and M3 (inter-arm variability): glycemic variability (%)	From enrollment to 3 months
The variability of CGM parameters according to the sensor placement site between M0 and M3 (inter-arm variability): mean glucose level (mg/dL)	The variability of CGM parameters according to the sensor placement site between M0 and M3 (inter-arm variability): mean glucose level (mg/dL)	From enrollment to 3 months
The variability of CGM parameters according to the sensor placement site between M0 and M3 (inter-arm variability): number of glucose excursions >200 mg/dL	The variability of CGM parameters according to the sensor placement site between M0 and M3 (inter-arm variability): number of glucose excursions >200 mg/dL	From enrollment to 3 months
The variability of CGM parameters according to the sensor placement site between M0 and M3 (inter-arm variability): estimated HbA1c (eA1c)	The variability of CGM parameters according to the sensor placement site between M0 and M3 (inter-arm variability): estimated HbA1c (eA1c)	From enrollment to 3 months
The variability of CGM parameters according to physical activity (percentage of daytime activity) : Variation in the number of steps	The variability of CGM parameters according to physical activity (percentage of daytime activity), Variation in the number of steps	From enrollment to 3 months and 6 months
The variability of CGM parameters according to body composition (body fat percentage)	The variability of CGM parameters according to body composition (body fat percentage) : body fat in kg	From enrollment to 3 months and 6 months
The variability of CGM parameters according to body composition	The variability of CGM parameters according to body composition (lean mass percentage) : body fat in kg	From enrollment to 3 months and 6 months
The variability of CGM parameters according to body composition (fat mass percentage in the dominant arm)	The variability of CGM parameters according to body composition (fat mass percentage in the dominant arm) : body fat in kg	From enrollment to 3 months and 6 months
The variability of CGM parameters according to body composition (fat mass percentage in the non-dominant arm) : body fat in kg	The variability of CGM parameters according to body composition (fat mass percentage in the non-dominant arm) : body fat in kg	From enrollment to 3 months and 6 months
The variability of CGM parameters according to nutritional intake : Daily nutritional intake (kcal)	The variability of CGM parameters according to nutritional intake : Daily nutritional intake (kcal)	From enrollment to 3 months and 6 months
The variability of CGM parameters according to nutritional intake : carbohydrates (kg)	The variability of CGM parameters according to nutritional intake : carbohydrates (kg)	From enrollment to 3 months ans 6 months
The variability of CGM parameters according to nutritional intake : fats (kg)	The variability of CGM parameters according to nutritional intake : fats (kg)	From enrollment to 3 months and 6 months
The variability of CGM parameters according to nutritional intake : proteins (kg)	The variability of CGM parameters according to nutritional intake : proteins (kg)	From enrollment to 3 months and 6 months

Collaborators and Investigators

• Sponsor: Hospices Civils de Lyon

Study record dates

Study Major Dates

• Study Start (Estimated): November 1, 2026
• Primary Completion (Estimated): February 1, 2028
• Study Completion (Estimated): May 1, 2028

Study Registration Dates

• First Submitted: September 21, 2026
• First Submitted That Met QC Criteria: September 25, 2026
• First Posted (Actual): October 1, 2026

Study Record Updates

• Last Update Posted (Actual): October 1, 2026
• Last Update Submitted That Met QC Criteria: September 25, 2026
• Last Verified: September 1, 2026

More Information

Terms related to this study

• Keywords: Continuous Glucose Monitoring; Cystic Fibrosis; Glucose metabolism disorders
• Additional Relevant MeSH Terms: Genetic Diseases, Inborn; Metabolic Diseases; Respiratory Tract Diseases; Digestive System Diseases; Lung Diseases; Infant, Newborn, Diseases; Pancreatic Diseases; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Nutritional and Metabolic Diseases; Cystic Fibrosis; Glucose Metabolism Disorders; Investigative Techniques; Clinical Laboratory Techniques; Diagnostic Techniques and Procedures; Diagnosis; Blood Chemical Analysis; Clinical Chemistry Tests; Diagnostic Techniques, Endocrine; Monitoring, Physiologic; Continuous Glucose Monitoring
• Other Study ID Numbers: 69HCL25_1040; 2026-A00194-47 (Other Identifier: ID-RCB)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No