CPAP and Glucose Metabolism in Non-Diabetic OSA Subjects

March 25, 2025 updated by: Woolcock Institute of Medical Research

The Impact of CPAP on Glucose Metabolism in Moderate-Severe Obstructive Sleep Apnoea Patients Without Diabetes - an Observational Study

The purpose of the current study is to investigate whether alleviation of OSA by CPAP positively impacts glucose metabolism in non-diabetic patients.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Glucose metabolism in patients newly diagnosed with moderate-severe OSA and without diabetes will be monitored for two weeks prior to commencement of CPAP using a CGM. They will consume a 75g oral glucose drink fasted on waking twice during the two-week monitoring period, having consumed a standardised meal the evening prior. After establishing CPAP use for at least four weeks they will undergo the same protocol as for the observation period prior to commencing CPAP. Glucose metabolism will be monitored using an interstitial (skin based) glucose monitor.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
100

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • Australia
    • New South Wales
      • Camperdown, New South Wales, Australia, 2050
        • Royal Prince Alfred Hospital
        • Contact:
        • Contact:
          • Professor Brendon Yee
      • Macquarie Park, New South Wales, Australia, 2113
        • Woolcock Institute of Medical Research
        • Contact:
        • Contact:
          • Craig Phillips, PhD
        • Contact:
          • Brendon Yee, PhD FRACP

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  1. Community dwelling adult males and females aged 18-65 years
  2. Polysomnography confirmed moderate to severe OSA with apnea hypopnea index (AHI) ≥15/hr within the past 60 months
  3. Able to give written informed consent
  4. Proficient in English

6. Diagnosed non-diabetic as defined by the American Diabetes Association as any of the following recent (<3 months) findings:

  1. Fasting glucose with a BGL <7.0 mmol/L
  2. Glucose tolerance with a 2-hour BGL of < 11.1 mmol/L after a formal 75g Oral Glucose Tolerance Test (OGTT)
  3. HbA1C of ≤ 6.5% 7. Possession or regular access to a mobile telephone with capability to download and run the Withings Sleep Anlayser App.

Exclusion Criteria:

  1. Clinically significant co-morbidity (e.g. myocardial infarction, congestive heart failure, stroke, arrythmia, chronic kidney or liver disease, epilepsy, head injury)
  2. Severe mental health disorders (e.g. current major depressive disorder, schizophrenia, bipolar disorder) that in the opinion of the investigator is not adequately treated or will significantly affect their participation in the study.
  3. Regular (>2 times per month) use of sleep-affecting medication (e.g. benzodiazepines, opioids, antidepressants)
  4. Regular night shift work or travel overseas within the last 2 weeks
  5. Sleep physician has advised against CPAP withdrawal
  6. Pregnancy
  7. Active smoking or routine alcohol use (more than 2 standard drinks a day) or excessive caffeine intake (>300 mg a day) or recent (in the past month) use of illicit drugs
  8. Current or previous diagnosis of diabetes mellitus (previous gestational diabetes mellitus not excluded)
  9. Current or recent (<3 months) use of hypoglycaemic agents
  10. Undergoing a weight loss programme
  11. Contraindications for use of the FreeStyle Libre Pro Sensor. E.g. Known hypersensitivity to skin adhesives such as those used to attach the sensor to the arm.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Non-Randomized
  • Interventional Model: Sequential Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
No Intervention: CPAP off condition
Participants will be monitored for a two-week period prior to commencing CPAP.
Experimental: CPAP on condition
Participants will be monitored for a two-week period at least four weeks following commencement of CPAP.
Device: CPAP
A positive CPAP intervention

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Mean 24 hour glucose difference between the CPAP on and CPAP off conditions
Time Frame: 2 weeks
Average 24 hour glucose difference between CPAP on and CPAP off conditions
2 weeks

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Mean daytime glucose difference between the CPAP on and CPAP off conditions
Time Frame: 2 weeks
Mean Daytime (6:00 AM - 10:00 PM) glucose difference between the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods.
2 weeks
Mean night time glucose
Time Frame: 2 weeks
Mean Night-time (10:00 PM - 6:00 AM) glucose difference between the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods.
2 weeks
Glucose tolerance
Time Frame: 2 weeks
Difference in glucose tolerance as measured by peak 2-hour post 75g glucose load administered twice during each two-week observation period using a CGM
2 weeks
Coefficient of Variation
Time Frame: 2 Weeks
Percentage CV intraday (i.e. within 24h) and interday (i.e. over multiple days) between the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods.
2 Weeks
SD of Mean Glucose
Time Frame: 2 Weeks
SD of Mean Glucose (daily) during the CPAP on and CPAP off conditions during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods.
2 Weeks
Time in Range (TIR)
Time Frame: 2 Weeks
Percentage of TIR (3.9-10.0 mmol/L) (hours and minutes) during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods.
2 Weeks
Time Below Range (TBR)
Time Frame: 2 Weeks
Percentage of TBR (3.9 mmol/L including readings of <3 .0 mmol/L) during the the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods.
2 Weeks
Time below Range <3.0 mmol/L
Time Frame: 2 Weeks
Percentage of TBR <3.0 mmol/L (hours and minutes) during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods.
2 Weeks
Time Above Range (TAR)
Time Frame: 2 Weeks
Percentage of TAR (>10.0 mmol/L, including readings >13.9 mmol/L) (hours and minutes) during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods.
2 Weeks
Time Above Range >13.9 mmol/L
Time Frame: 2 Weeks
Percentage of TAR >13.9 mmol/L (hours and minutes) during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods.
2 Weeks
Time in Tight Range (TITR)
Time Frame: 2 Weeks
Percentage of TITR (3.9-7.8 mmol/L) (hours and minutes) during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods.
2 Weeks
Change in Glucose Management Indicator
Time Frame: 2 Weeks
Absolute main change in mmol/L or percentage during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods.
2 Weeks
Extended hypoglycaemic event rate
Time Frame: 2 Weeks
Number of events with sensor glucose <3.9 mmol/L lasting at least 120 min, event ends when glucose returns to at least 3.9 mmol/L for at least 15 minutes during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods.
2 Weeks
Extended hyperglycaemic event
Time Frame: 2 Weeks
Number of events with sensor glucose >13.9 mmol/L lasting at least 120 min; event ends when glucose returns to 10 mmol/L or less for at least 15 minutes during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods.
2 Weeks
TIR >70%
Time Frame: 2 Weeks
Proportion of participants with TIR 3.9-10.0 mmol/L for >70% of the day during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods.
2 Weeks
TIR improvement at least 5%
Time Frame: 2 Weeks
Proportion of participants with TIR 3.9-10.0 mmol/L with at least a 5% improvement from baseline during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods.
2 Weeks
TIR improvement at least 10%
Time Frame: 2 Weeks
Proportion of participants with TIR 3.9-10.0 mmol/L with at least a 10% improvement from baseline during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods.
2 Weeks
TBR <3.9 mmol/L <4%
Time Frame: 2 Weeks
Proportion of participants with TBR <3.9 mmol/L for <4% of each day during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods.
2 Weeks
TBR <3.0 mmol/L <1%
Time Frame: 2 Weeks
Proportion of participants with TBR <3.0 mmol/L for <1% of each day during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods.
2 Weeks
TAR >10.0 mmol/L >25%
Time Frame: 2 Weeks
Proportion of participants with a TAR >10.0 mmol/L for <25% of each day during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods.
2 Weeks
TAR >13.9 mmol/L <5%
Time Frame: 2 Weeks
Proportion of participants with TAR >13.9 mmol/L for <5% of each day during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods.
2 Weeks
Hypoglycaemia
Time Frame: 2 Weeks
Number of times CGM sensor values are <3.9 mmol/L (including readings of <3.0 mmol/L) for at least 15 consecutive minutes during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods. The event ends when there is at least 15 consecutive minutes with a CGM sensor value at least 3.9 mmol/L.
2 Weeks
Hypoglycaemia Alert Value (Level 1)
Time Frame: 2 Weeks
Number of times CGM sensor values are 3.0-3.9 mmol/L for at least 15 consecutive minutes during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods. The event ends when there is at least 15 consecutive minutes with a CGM sensor value at least 3.9 mmol/L.
2 Weeks
Clinically Significant Hypoglycaemia (Level 2)
Time Frame: 2 Weeks
Number of times CGM sensor values are <3.0 mmol/L for at least 15 consecutive minutes during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods. The event ends when there is at least 15 consecutive minutes with a CGM sensor value at least 3.0 mmol/L.
2 Weeks
Extended Hypoglycaemia
Time Frame: 2 Weeks
Number of times CGM sensor values are <3.9 mmol/L for at least 120 consecutive minutes during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods.
2 Weeks
High Glucose Level (Level 1)
Time Frame: 2 Weeks
Number of times CGM sensor values are 10.1-13.9 mmol/L for at least 15 consecutive minutes during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods. The event ends when there is at least 15 consecutive minutes with a CGM sensor value at or below 10 mmol/L.
2 Weeks
Very High Glucose (Level 2)
Time Frame: 2 Weeks
Number of times CGM sensor values are >13.9 mmol/L for at least 15 consecutive minutes during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods. The event ends when there is at least 15 consecutive minutes with a CGM sensor value at or below 13.9 mmol/L.
2 Weeks
Extended Hyperglycaemia
Time Frame: 2 Weeks
Number of times CGM sensor values are >13.9 mmol/L for at least 90 consecutive minutes within a 120-minute period during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods.
2 Weeks

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
TIR Improvement >10% and <0.5% increase in TBR <3.0 mmol/L
Time Frame: 2 Weeks
Proportion of participants with >10% improvement in percentage of TIR 3.9-10.0 mmol/L without an increase in the TBR <3.0 mmol/L of >0.5% during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods.
2 Weeks
Mean Glucose <8.6 mmol/L and <1% TBR <3.0 mmol/L
Time Frame: 2 Weeks
Proportion of participants with Mean Glucose <8.6 mmol/L and < 1% TBR <3.0 mmol/L during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods.
2 Weeks
TIR >70% and <1% TBR <3.9 mmol/L
Time Frame: 2 Weeks
Proportion of participants with >70% TIR 3.9-10.0mmol/L and <4% TBR <3.9 mmol/L during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods.
2 Weeks
TIR >70% and < 1% TBR <3.0 mmol/L
Time Frame: 2 Weeks
Proportion of participants with >70% TIR 3.9-10.0 mmol/L and <1% TBR <3.0 mmol/L during the CPAP on and CPAP off conditions as measured by the FreeStyle Libre Pro sensor during the 2-week intervention periods.
2 Weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Woolcock Institute of Medical Research

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Craig L Phillips, PhD, Woolcock Institute of Medical Research

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 1, 2025

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
February 28, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
February 28, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
April 12, 2022

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 12, 2022

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
April 19, 2022

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 1, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 25, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
March 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2021/ETH12082

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

All data will be deidentified using a unique study ID.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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