An observational study in Obstructive Sleep Apnea and Cardiovascular (CV) Risk, sponsored by University Hospital, Antwerp. Recruiting at 1 site in Belgium. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-06-29.
Sponsored by University Hospital, Antwerp · Observational
The goal of this prospective study is to gain insight into the endophenotypic variation in OSA, with a focus on the underlying pathophysiological traits and the cardiovascular alterations associated with the condition. To capture the variability in OSA endophenotypes, novel metrics that extend beyond the AHI will be considered, with particular attention to the sleep-apnea-specific hypoxic burden, the sleep-apnea-specific heart rate response, and pulse wave amplitude drops (PWADs). Since the impact of treatment on cardiovascular parameters remains an important point of interest, the effects of different treatment modalities on cardiovascular changes will be investigated, including continuous positive airway pressure (CPAP), mandibular advancement devices (MADs), and hypoglossal nerve stimulation.
2,240 studies on the registry are indexed under Sleep Apnea, Obstructive; 475 are open to participants now.
This study's planned enrollment of 270 is above the median of 105 across 666 observational studies indexed under Sleep Apnea, Obstructive.
Browse Sleep Apnea, Obstructive studies →University Hospital, Antwerp is the lead sponsor of 242 studies on the registry; 66 are open to participants now.
Counted across the registry records on this site, refreshed daily.
The study population consists of patients diagnosed with moderate to severe obstructive sleep apnea (OSA) (AHI≥15/h), recruited by the OSA multidisciplinary team.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
CPAP remains the most commonly used treatment modality and is considered as the gold standard for patients with OSA because of its high efficacy and noninvasive nature. CPAP therapy is indicated for patients with moderate to severe OSA (AHI ≥ 15/h) or for those with a lower AHI with symptoms of excessive daytime sleepiness. It is effective in reducing nocturnal obstructive events by delivering continuous positive airway pressure, which functions as a pneumatic splint to keep the upper airway open and prevent pharyngeal collapse during sleep \[16\]. CPAP therapy generally improves sleep parameters, enhances blood oxygen saturation and causes disappearing of OSA-related symptoms. Although CPAP is really effective in treating OSA, many patients struggle with intolerance and long-term adherence remains a significant challenge.
Mandibular advancement device (MAD) has become a widely recognized non-invasive treatment alternative for patients who cannot tolerate CPAP. It is primarily indicated for mild to moderate OSA and lately also for severe OSA patients. These MADs are worn intraorally during the night and attach to both upper and lower dental arches, protrude the lower jaw to widen and reopen the upper airway.
Hypoglossal nerve stimulation (HNS) is a novel and unique therapeutic option for patients with moderate-to-severe OSA who cannot be treated effectively with CPAP or MAD. In contrast to traditional reconstructive procedures for OSA, which focus only on anatomical adjustments, HNS integrates a surgical implantation process with an adjustable medical device to open the upper airway through neuromodulation of the hypoglossal nerve.
Cardiovascular outcome: interventricular septum thickness
Interventricular septal thickness will be assessed via 2D-guided M-mode echocardiographic measurements in the parasternal long-axis view.
Time frame: 1 year
Sleep apnea-specific hypoxic burden (SASHB)
This novel metric is calculated by determining the total area under the respiratory event-related desaturation curve, which can be obtained from a polysomnography (PSG). It has been shown to be a good predictor of cardiovascular disease mortality, but has not yet been established in daily practice.
Time frame: 1 year
Heart rate response to a respiratory event (ΔHR)
ΔHR is defined as the difference between the maximum pulse rate after airway opening, i.e. during a subject-specific search window, and an event-related minimum pulse rate, i.e. minimum pulse rate during respiratory events. ΔHR will be calculated from a photoplethysmography (PPG), a signal derived from a finger pulse oximeter, which is part of the standard clinical PSG set-up.
Time frame: 1 year
Pulse wave amplitude drops (PWADs)
PWADs can be calculated from photoplethysmography (PPG), a signal derived from a finger pulse oximeter, which is part of the standard clinical PSG set-up.
Time frame: 1 year
Cardiovascular outcome: heart rate variability
Heart rate variability will be calculated from ECG-derived RR intervals obtained during the sleep study.
Time frame: 1 year
Cardiovascular outcome: left ventricular ejection fraction
Left ventricular ejection fraction will be assessed via 2D-guided M-mode echocardiographic measurements in the parasternal long-axis view.
Time frame: 1 year
Cardiovascular outcome: left ventricular mass
Left ventricular mass will be assessed via 2D-guided M-mode echocardiographic measurements in the parasternal long-axis view.
Time frame: 1 year
Cardiovascular outcome: 24-hour ambulatory blood pressure
24-hour ambulatory blood pressure will be measured using ambulatory blood pressure monitoring (ABPM).
Time frame: 1 year
Cardiovascular outcome: systolic and diastolic function
Left ventricular systolic and diastolic function will be evaluated using 2D echocardiography. Systolic function will be quantified by left ventricular ejection fraction calculated using the Simpson biplane method. Diastolic function will be assessed using pulsed wave tissue Doppler imaging at the septal and lateral mitral annulus, mitral inflow velocities (E/A ratio), the E/e' ratio and left atrial volume index.
Time frame: 1 year
OSA efficacy: delta apnea-hypopnea index (AHI)
The apnea-hypopnea Index (AHI), defined as the number of apneas (cessations in breathing) and hypopneas (reductions in airflow) per hour of sleep measured during a polysomnography, will be assessed. OSA is diagnosed when the AHI is at least 5/h. The AHI classifies OSA as mild with AHI ranging from 5 to 14.9 events per hour, moderate with AHI ranging from 15 to 29.9 events per hour and severe when 30 or higher events per hour.
Time frame: 1 year
Oxygen desaturation index (ODI)
The oxygen desaturation index (ODI) represents the number of oxygen desaturation events per hour of sleep, typically defined as a ≥3% or ≥4% drop in arterial oxygen saturation from baseline.
Time frame: 1 year
Therapy adherence defined by the amount of hours of therapy usage per night and the number of nights per week of use
Average hours of therapy use per night and the number of nights per week can be retrieved from data stored in the device.
Time frame: 1 year
Degree of snoring measured by Visual Analogue Scale (VAS)
Visual analogue scale for snoring, from 0 to 10: 0 represents no snoring, 1-3 represents minimally annoying, 4-6 represents moderately annoying, 7-9 represents annoying, and 10 represents extremely annoying.
Time frame: 1 year
Daytime sleepiness measured by the Epworth Sleepiness Scale (ESS) questionnaire
Daytime sleepiness measured using the Epworth sleepiness scale (ESS), which is a self-administered questionnaire that assesses the likelihood of falling asleep in various settings and situations in daily life.The questionnaire consists of eight items scored from 0 to 3, resulting in a total score ranging from 0 to 24. The lowest score (zero) suggests that the described incident is absent and the highest score (three) suggests the presence of this event.
Time frame: 1 year
Fatigue measured by the Checklist Individual Strength (CIS) questionnaire
Fatigue was assessed using the checklist individual strength, a 20-item questionnaire with each item scored on a 7-point Likert scale, resulting in total scores ranging from 20 to 140. Higher scores indicate greater fatigue severity.
Time frame: 1 year
Started Jun 2026 (actual). Primary completion is estimated for Dec 2029, 42 months after the start.
Of 258 non-industry observational studies under Sleep Apnea, Obstructive, half reached primary completion within 31 months of starting (the median), counting those still running; a quarter within 16 and three quarters within 61. This study's planned 42 months is above that.
Counting every sponsor, half of 294 studies reached it within 28 months; a quarter within 14 and three quarters within 63.
How these figures are worked out, and which studies are left out of them.
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