The purpose of the current study is to investigate whether alleviation of OSA by CPAP positively impacts glucose metabolism in non-diabetic patients.
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
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
100
A positive CPAP intervention
Royal Prince Alfred Hospital
Camperdown, New South Wales, Australia
Woolcock Institute of Medical Research
Macquarie Park, New South Wales, Australia
Mean 24 hour glucose difference between the CPAP on and CPAP off conditions
Average 24 hour glucose difference between CPAP on and CPAP off conditions
Time frame: 2 weeks
Mean daytime glucose difference between the CPAP on and CPAP off conditions
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.
Time frame: 2 weeks
Mean night time glucose
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.
Time frame: 2 weeks
Glucose tolerance
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 frame: 2 weeks
Coefficient of Variation
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.
Time frame: 2 Weeks
SD of Mean Glucose
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 frame: 2 Weeks
Time in Range (TIR)
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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 frame: 2 Weeks
Time Below Range (TBR)
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 frame: 2 Weeks
Time below Range <3.0 mmol/L
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 frame: 2 Weeks
Time Above Range (TAR)
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 frame: 2 Weeks
Time Above Range >13.9 mmol/L
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.
Time frame: 2 Weeks
Time in Tight Range (TITR)
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.
Time frame: 2 Weeks
Change in Glucose Management Indicator
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.
Time frame: 2 Weeks
Extended hypoglycaemic event rate
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.
Time frame: 2 Weeks
Extended hyperglycaemic event
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.
Time frame: 2 Weeks
TIR >70%
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.
Time frame: 2 Weeks
TIR improvement at least 5%
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.
Time frame: 2 Weeks
TIR improvement at least 10%
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.
Time frame: 2 Weeks
TBR <3.9 mmol/L <4%
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.
Time frame: 2 Weeks
TBR <3.0 mmol/L <1%
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.
Time frame: 2 Weeks
TAR >10.0 mmol/L >25%
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.
Time frame: 2 Weeks
TAR >13.9 mmol/L <5%
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.
Time frame: 2 Weeks
Hypoglycaemia
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.
Time frame: 2 Weeks
Hypoglycaemia Alert Value (Level 1)
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.
Time frame: 2 Weeks
Clinically Significant Hypoglycaemia (Level 2)
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.
Time frame: 2 Weeks
Extended Hypoglycaemia
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.
Time frame: 2 Weeks
High Glucose Level (Level 1)
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.
Time frame: 2 Weeks
Very High Glucose (Level 2)
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.
Time frame: 2 Weeks
Extended Hyperglycaemia
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.
Time frame: 2 Weeks