Type 1 Diabetes MellitusNCT05144802

Accuracy of Dexcom G6® and FreeStyle Libre® Sensors in Standardized Hypoxemia Conditions

A study testing acute hypoxia in people with Type 1 Diabetes Mellitus and Type 2 Diabetes Mellitus, run by Poitiers University Hospital at 1 site in France.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial summary

The major aim is to evaluate accuracy of 2 Continuous Glucose Monitoring Systems (CGMS) : Dexcom G6® and FreeStyle Libre® in standardized hypoxemia conditions (artificial normobaric hypoxia). Our purpose is to demonstrate the good performance and calibration of these CGM sensors in hypoxemia conditions. Read more about this study

Who is it for?: Ages 18 to 75 yearsHealthy volunteers can take part
Conditions the study is for: Type 1 Diabetes Mellitus, Type 2 Diabetes Mellitus
What is being tested?: acute hypoxia
Type of treatment: Surgery or procedure
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 30 participants
Where: 1 siteFrance
Study dates: 16 May 2022to 28 Jan 2025
Phase: Interventional
Are there results?: Yes, posted in the registrySummary in the doctors' view

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 75 years
All sexes
Healthy volunteers accepted
Adult, Older adult

Who may be able to join

No history of respiratory diseases (childhood asthma, respiratory allergies, exercise-induced asthma or dyspnea)
Willing to participate and able to sign an informed consent form (ICF)
Being affiliated with the French Social Security
type 1 diabetes mellitus or type 2 diabetes mellitus (ADA definition)
Age : 18 to 75 years
stable diabetes treatment for more than 3 months

Show all 39Show fewer

no diabetic retinopathy
no diabetic neuropathy
no cardiovascular diseases
no contra-indication for coronary computed tomography angiography or myocardial perfusion scintigraphy.
Age : 18 ; 40 years
No diabetes
No persistant drug use > 3 months except contraception
Body mass index : [18,5 - 29,9] kg/m2
Non-inclusion criteria : all population
Active smokers
Pregnant or breastfeeding women, women of childbearing age without effective contraception
Known allergies to the patch.
Skin lesions at the sensor site that may interfere with sensor placement or accuracy
Major cardiovascular complications within the past 3 months
Decompensated congestive heart failure
Chronic respiratory failure
Chronic renal failure
Resting ambient air O2 saturation ≤95%.
Treatment with systemic corticosteroids
Severe hypertension (≥180 mmHg systolic pressure or ≥ 100 mmHg diastolic pressure)
Any concomitant disease or condition that the investigator believes may compromise patient safety or affect the conduct of the study
Anemia (Hb<12g/dl)
History of severe mountain sickness
Concurrent participation in another clinical research study,
Persons benefiting from enhanced protection
Non-inclusion criteria: Patients with diabetes
Absolute contraindications to physical activity (HAS definitin) :
Pulmonary arterial hypertension (> 60 mm Hg)
Presence of intra-cardiac thrombus
Acute pericardial effusion
Severe obstructive cardiomyopathy
Symptomatic aortic stenosis
Recent thrombophlebitis with or without pulmonary embolism

Who cannot join

None listed.

Trial locations and contacts

1 site in 1 country.

France1 site

CHU
Poitiers, 86000

Other trials in France

About this study

The major aim is to evaluate accuracy of 2 Continuous Glucose Monitoring Systems (CGMS) : Dexcom G6® and FreeStyle Libre® in standardized hypoxemia conditions (artificial normobaric hypoxia).

Our purpose is to demonstrate the good performance and calibration of these CGM sensors in hypoxemia conditions.

Conditions: Type 1 Diabetes Mellitus, Type 2 Diabetes Mellitus
Being tested: acute hypoxia
Keywords: CGM (Continuous Glucose Monitoring)
Medical subject headings: Diabetes Mellitus, Type 1, Diabetes Mellitus, Type 2

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

acute hypoxiaProcedure or surgery
Participants will be exposed to a 3-hour acute hypoxia

Study groups in NCT05144802
Study group	Role	What they receive
group 1 : FreeStyle Libre 2 on right arm and Dexcom G6 on left arm	Experimental	In this group, participants will be continuously monitored for their interstitial glucose level with 2 CGM devices : FreeStyle Libre 2 will be applied on right arm and Dexcom G6 will be applied on left arm. Receives: Procedure: acute hypoxia
group 2 : 2 FreeStyle Libre 2 on left arm and Dexcom G6 on right arm	Active comparator	In this group, participants will be continuously monitored for their interstitial glucose level with 2 CGM devices : Dexcom G6 will be applied on right arm and FreeStyle Libre 2 will be applied on left arm. Receives: Procedure: acute hypoxia

What is being measured

The primary outcome is the main question the study is designed to answer.

Mean Absolute Relative Difference (MARD)
The primary endpoint for measuring the accuracy of CGMs (individually) compared to venous blood glucose was the mean absolute relative difference, expressed as a percentage. As the percentages obtained did not follow a normal distribution, they are expressed in the table as median and IQR.
Measured: Day 1

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

16 May 202228 Jan 2025

First posted3 Dec 2021
Study start16 May 2022
Primary completion28 Jan 2025
Study completion28 Jan 2025

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Publications (1)Papers the sponsor has linked to this study.
Other trials for Type 1 Diabetes MellitusStudies of the same condition, open and under way.
More trials run by Poitiers University HospitalThe sponsor's other registered studies.
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: Basic science
Allocation: Randomised
Intervention model: Parallel groups
Masking: None (open label)
Enrolment: 30 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT05144802
Sponsor's protocol ID: FOX
Status last verified: Oct 2026
First submitted: 29 Oct 2021
Last updated: 3 Nov 2026
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: No
FDA-regulated drug: No
FDA-regulated device: No

Publications

Bassas Letissier N, Rault C, Faucher C, Rabois E, Durocher L, Bouleti C, Ragot S, Hadjadj S, Mosbah H, Piguel X, Alos B, Thuillier R, Saulnier PJ. Accuracy of Dexcom G6(R) and FreeStyle Libre(R) Sensors in Standardized Hypoxia Conditions: A Randomized Controlled Trial-FOX Study. Diabetes Technol Ther. 2026 Feb 17:15209156261423954. doi: 10.1177/15209156261423954. Online ahead of print.
PubMed 41703423

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

See locations

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Study at a glance

From the registry record, last updated by the sponsor on 3 Nov 2026. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Accuracy of Dexcom G6® and FreeStyle Libre® Sensors in Standardized Hypoxemia Conditions
ClinicalTrials.gov ID: NCT05144802
Acronym / sponsor ID: FOX
Conditions: Type 1 Diabetes Mellitus, Type 2 Diabetes Mellitus
Keywords: CGM (Continuous Glucose Monitoring)
Study type: Interventional
Recruitment status: Completed
Enrolment: 30 participants (actual)
Lead sponsor: Poitiers University HospitalUniversity, hospital or other
Study start: 16 May 2022 (actual)
Primary completion: 28 Jan 2025 (actual)
Study completion: 28 Jan 2025 (actual)
First posted: 3 Dec 2021 (actual)
Results: Posted 17 Jun 2026

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

The major aim is to evaluate accuracy of 2 Continuous Glucose Monitoring Systems (CGMS) : Dexcom G6® and FreeStyle Libre® in standardized hypoxemia conditions (artificial normobaric hypoxia).

Our purpose is to demonstrate the good performance and calibration of these CGM sensors in hypoxemia conditions.

Study design

Primary purpose: Basic science
Allocation: Randomised
Intervention model: Parallel groups
Masking: None (open label)
Number of arms: 2

Arm	Type	Receives
group 1 : FreeStyle Libre 2 on right arm and Dexcom G6 on left arm	Experimental	Procedure: acute hypoxiaIn this group, participants will be continuously monitored for their interstitial glucose level with 2 CGM devices : FreeStyle Libre 2 will be applied on right arm and Dexcom G6 will be applied on left arm.
group 2 : 2 FreeStyle Libre 2 on left arm and Dexcom G6 on right arm	Active comparator	Procedure: acute hypoxiaIn this group, participants will be continuously monitored for their interstitial glucose level with 2 CGM devices : Dexcom G6 will be applied on right arm and FreeStyle Libre 2 will be applied on left arm.

Who may qualify

Ages: 18 to 75 years
Sex: All
Healthy volunteers: Accepted
Age groups: Adult, Older adult

Key inclusion criteria (39 listed)

No history of respiratory diseases (childhood asthma, respiratory allergies, exercise-induced asthma or dyspnea)
Willing to participate and able to sign an informed consent form (ICF)
Being affiliated with the French Social Security
type 1 diabetes mellitus or type 2 diabetes mellitus (ADA definition)
Age : 18 to 75 years

Key exclusion criteria (0 listed)

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
acute hypoxiaParticipants will be exposed to a 3-hour acute hypoxia	Procedure or surgery	group 1 : FreeStyle Libre 2 on right arm and Dexcom G6 on left arm, group 2 : 2 FreeStyle Libre 2 on left arm and Dexcom G6 on right arm

Primary outcome

Mean Absolute Relative Difference (MARD)
Time frame: Day 1
The primary endpoint for measuring the accuracy of CGMs (individually) compared to venous blood glucose was the mean absolute relative difference, expressed as a percentage. As the percentages obtained did not follow a normal distribution, they are expressed in the table as median and IQR.

Results and safety

Results posted to the registry on 17 Jun 2026, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Group 1	15	15
Group 2	15	15

Primary outcome: Mean Absolute Relative Difference (MARD)

Time frame: Day 1. Median (Inter-Quartile Range). Unit: percent

Measure	Healthy Volunteers n = 15	Participants With Diabetes n = 15
Freestyle CGM	21.2 (16.6 to 37.9)	11.8 (6.5 to 17.6)
Dexcom CGM	41.8 (26.9 to 69.7)	17.5 (14.3 to 23.5)

Adverse events

Time frame: During the 3-hour hypoxia exposure. Other adverse events reported at 0% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Healthy Volunteers	1 of 15 (6.7%)	2 of 15 (13.3%)	0 of 15
Participants With Diabetes	0 of 15 (0%)	2 of 15 (13.3%)	0 of 15

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 3 Nov 2026.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Results publication: PubMed 41703423Bassas Letissier N, Rault C, Faucher C, Rabois E, Durocher L, Bouleti C, Ragot S, Hadjadj S, Mosbah H, Piguel X, Alos B, Thuillier R, Saulnier PJ. Accuracy of Dexcom G6(R) and FreeStyle Libre(R) Sensors in Standardized Hypoxia Conditions: A Randomized Controlled Trial-FOX Study. Diabetes Technol Ther. 2026 Feb 17:15209156261423954. doi: 10.1177/15209156261423954. Online ahead of print.

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Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

The record lists no contact. Use the official record to reach the sponsor.

1 site in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

A study testing acute hypoxia in people with Type 1 Diabetes Mellitus and Type 2 Diabetes Mellitus, run by Poitiers University Hospital at 1 site in France.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 39 inclusion and 0 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 3 Nov 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in France. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

Yes. Results are posted in the registry (first posted 17 Jun 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Mean Absolute Relative Difference (MARD) (time frame: Day 1). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05144802, which also lists 1 linked publication.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Nov 2026.