CPAP and Glucose Metabolism in Non-Diabetic OSA Subjects

Not Applicable

Not yet recruiting

• Conditions: Obstructive Sleep Apnea; Pre-diabetes
• Interventions: Device: CPAP

• Registration Number: NCT05335083
• Lead Sponsor: Woolcock Institute of Medical Research

Brief Summary

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

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 Timeline

• Study First Submitted: 2022-04-12
• Study First Submitted QC: 2022-04-12
• Study First Posted: 2022-04-19
• Status Verified: 2025-03
• Last Update Submitted: 2025-03-25
• Last Update Posted: 2025-04-01
• Study Start: 2025-07-01
• Primary Completion: 2027-02-28
• Study Completion: 2027-02-28

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 100

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

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

6. Fasting glucose with a BGL <7.0 mmol/L

7. Glucose tolerance with a 2-hour BGL of < 11.1 mmol/L after a formal 75g Oral Glucose Tolerance Test (OGTT)

8. 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 & Design

• Study Type: INTERVENTIONAL
• Study Design: SEQUENTIAL

Arm && Interventions

Group	Intervention	Description
CPAP on condition	CPAP	Participants will be monitored for a two-week period at least four weeks following commencement of CPAP.

Primary Outcome Measures

Name	Time	Method
Mean 24 hour glucose difference between the CPAP on and CPAP off conditions	2 weeks	Average 24 hour glucose difference between CPAP on and CPAP off conditions

Secondary Outcome Measures

Name	Time	Method
Mean daytime glucose difference between the CPAP on and CPAP off conditions	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.
Change in Glucose Management Indicator	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.
Mean night time glucose	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.
Coefficient of Variation	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.
SD of Mean Glucose	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.
Time in Tight Range (TITR)	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.
Glucose tolerance	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
Time in Range (TIR)	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.
Time Below Range (TBR)	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.
Time below Range <3.0 mmol/L	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.
Time Above Range (TAR)	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.
Time Above Range >13.9 mmol/L	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.
Extended hypoglycaemic event rate	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.
Extended hyperglycaemic event	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.
TIR >70%	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.
TIR improvement at least 5%	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.
TIR improvement at least 10%	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.
TBR <3.9 mmol/L <4%	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.
TBR <3.0 mmol/L <1%	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.
TAR >10.0 mmol/L >25%	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.
TAR >13.9 mmol/L <5%	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.
Hypoglycaemia	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.
Hypoglycaemia Alert Value (Level 1)	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.
Clinically Significant Hypoglycaemia (Level 2)	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.
Extended Hypoglycaemia	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.
High Glucose Level (Level 1)	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.
Very High Glucose (Level 2)	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.
Extended Hyperglycaemia	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.

Trial Locations

Locations (2)

Royal Prince Alfred Hospital; 🇦🇺 Camperdown, New South Wales, Australia

Woolcock Institute of Medical Research; 🇦🇺 Macquarie Park, New South Wales, Australia