None listed
Conditions
Brief summary
We are studying how much blood pressure and blood sugar vary across nights in people who have both obstructive sleep apnoea and high blood pressure. We want to see whether using a continuous positive airway pressure (CPAP) machine every night for about eight hours can help keep these levels more stable. We will look at how CPAP affects people’s blood pressure, blood sugar, and energy levels, both in a controlled laboratory setting and during everyday life at home. We will also explore whether factors such as diet, sleep habits, or teeth grinding influence these changes.
Interventions
The participants will attend Night 1 in the sleep laboratory and complete a baseline assessment. On the first night, participants will not be fitted with a positive airway pressure (PAP) machine, allowing them to adjust to the in-lab environment and fall asleep naturally. Upon waking (ad libitum if required), participants will undergo a standard morning blood pressure measurement and an oral glucose tolerance test (OGTT) with 75 g of glucose, followed by a 2-hour post-load assessment. Blood gluc
The participants will attend Night 1 in the sleep laboratory and complete a baseline assessment. On the first night, participants will not be fitted with a positive airway pressure (PAP) machine, allowing them to adjust to the in-lab environment and fall asleep naturally. Upon waking (ad libitum if required), participants will undergo a standard morning blood pressure measurement and an oral glucose tolerance test (OGTT) with 75 g of glucose, followed by a 2-hour post-load assessment. Blood glucose levels will be recorded and another bout of alertness assessment will be completed using the Psychomotor Vigilance Test (PVT), Karolinska Sleepiness Scale (KSS) and Karolinska Drowsiness Test (KDT). Participants will then be allowed to leave the sleep laboratory, returning for Night 2. The Continuous Glucose Monitor (CGM) will remain attached subcutaneously in the posterior triceps area, and participants will be asked to photograph all main meals and snacks using their smartphone and complete a diet recall pre-sleep. Optimal PAP intervention in the sleep laboratory (Nights 2-10) From Night 2 onward, after completing the evening alertness testing, participants will be fitted with polysomnography (PSG), continuous blood glucose monitoring, blood pressure monitor, and a PAP machine will be applied. Participants will continue this routine for 9 consecutive nights of PAP (8 hours per night or until natural wake ad libitum), totalling 10 nights in the sleep laboratory. Each session will be deemed complete upon completion of evening and morning assessments of blood pressure, the PVT, KSS, and KDT. At the end of the 10th night, following morning blood pressure and alertness testing, a repeat OGTT will be performed, and all the baseline questionnaires will be administered again. Direct monitoring of adherence to be done at the Lab. Home PAP intervention extension phase (Nights 11-31) Upon successful completion of the in-lab phase, participants will be provided with the PAP machine which they used for the duration of the study, an under-mattress sleep analyser, blood pressure monitor, oximeter ring, and CGM for an additional 21 nights at home. Devices will need to be connected to the participant’s smartphone and home internet. Participants may opt out of this stage if they are uncomfortable. Those who opt in will continue photographing their meals and maintaining a diet log for the 21-day at-home phase, consistent with in-lab procedures. Indirect monitoring of adherence using CGM and under-mattress sensors to detect AHI level fluctuation from baseline.
Sponsors
Flinders University
Study design
Allocation
Non-randomised trial
Primary purpose
Treatment
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
Potential participants will be recruited from clinic referral, Flinders sleep research volunteer registry, directly from community via advertising or population who have previously consented to the Southern Adelaide Local Health Network (SALHN)-approved study (ID LR/SAC/24/045.24) on at-home assessment of OSA and are currently within their ongoing participation pool. Only individuals meeting the study’s inclusion and exclusion criteria will be eligible to participate. Inclusion criteria 1. Adults aged 18 years and over. 2. Patients with both hypertension and obstructive sleep apnoea (OSA): o OSA with undiagnosed/untreated, but persistent office or home blood pressure at or above 130/90 mmHg, or o OSA with clinically diagnosed hypertension on stable antihypertensive therapy for more than 3 months. 3. Participants classified into OSA severity groups based on Apnoea–Hypopnoea Index: o Only those in the lower (stable) and upper (unstable) tertile of standard deviation of AHI in OSA severity (from 1-month at-home monitoring) will be invited. 4. Willingness and ability to comply with all study procedures (in-lab nights, CPAP use, continuous glucose and blood pressure monitoring, psychomotor testing, questionnaires, and meal photography).
Exclusion criteria
Exclusion criteria 1. Unstable or recent (15% or recurrent severe hypoglycaemia). Medication that severely alter insulin secretion such as GLP-1 agonists can also confound outcomes and therefore participants prescribed with medication such as Tirzepatide or Semaglutide will be excluded. 2. Physician-indicated contraindication to CPAP or nasal instrumentation, such as severe uncorrectable nasal obstruction, recent major upper-airway surgery, recurrent severe epistaxis, or severe claustrophobia. 3. Uncontrolled metabolic conditions likely to confound outcomes, such type 2 diabetes (HbA1c >15% or recurrent severe hypoglycaemia). Medication that severely alter insulin secretion such as GLP-1 agonists can also confound outcomes and therefore participants prescribed with medication such as Tirzepatide or Semaglutide will be excluded. .
Outcome results
None listed