Obesity Hypoventilation Syndrome (OHS)PHOEBINCT04025528
Pathophysiology of Hypoventilation in Obesity and Effects of Bariatric Intervention
An observational study of Obesity Hypoventilation Syndrome (OHS), run by Guy's and St Thomas' NHS Foundation Trust at 1 site in United Kingdom.
Trial summary
Breathing is impacted by obesity. Early changes are characterised by significant breathing abnormalities during sleep (a condition called sleep disordered breathing, the most common of which is obstructive sleep apnoea). Read more about this study
- Who is it for?
- Ages 18 to 80 yearsHealthy volunteers can take part
- Conditions the study is for
- Obesity Hypoventilation Syndrome (OHS)
- What is being tested?
- Bariatric Surgery
- Type of treatment
- Surgery or procedure
- How many people
- 30 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 20 Jun 2019to Jul 2024
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 80 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Study population: Obese patients who are considering bariatric surgery intervention
Who may be able to join
- Patients 18 years or older
- BMI > 40
- Patients with significant sleep disordered breathing requiring treatment
- Patient is being assessed for bariatric surgery for either gastric sleeve or gastric bypass surgery
Who cannot join
- Patients with decompensated hypercapnic respiratory failure (pH< 7.3)
- Chronic hypercapnic respiratory failure due to a cause other than obesity such as neuromuscular, chest wall or airway disease
- Unstable cardiac disease including coronary artery disease and heart failure
- Significant co-morbid psychiatric disease requiring anti-psychotic medications
- Chronic pain syndrome on high dose opioid medications
- Treatment for drug or alcohol addiction
Show all 10Show fewer
- Cognitive impairment that would prevent informed consent
- Pregnancy
- Need for long-term renal replacement therapy
- Patients who undergo bariatric intervention with gastric balloon or gastric band.
Trial locations and contacts
1 site in 1 country.
United Kingdom1 site, 1 recruiting
- Recruiting
Guy's and St Thomas' NHS Trust
London, SE17EH
Michael Cheng, MBBS, +44 02071888070, michael.cheng@gstt.nhs.uk
About this study
Official title: Pathophysiology of Hypoventilation in Obesity and Effects of Bariatric Intervention: PHOEBI Study
Breathing is impacted by obesity. Early changes are characterised by significant breathing abnormalities during sleep (a condition called sleep disordered breathing, the most common of which is obstructive sleep apnoea). As the breathing changes worsen in severity, it may result in a rise in carbon dioxide levels during daytime causing a condition called obesity hypoventilation syndrome (OHS). The current treatment for obesity related breathing changes include supportive breathing therapy at night, optimisation of associated medical conditions and weight loss.
Weight management is an important part of obesity treatment. Weight loss strategies such as life-style modification do not always work. Weight loss surgery (bariatric surgery) has been shown to be an effective weight management intervention with long-term results. This study aims to understand breathing changes that occurs due to obesity and their resolution after weight loss surgery. The investigators are aiming to recruit participants with sleep disordered breathing who are currently awaiting bariatric surgery. In particular, the investigators are interested in comparing breathing changes in participants with OHS, who have abnormal regulation of their carbon dioxide levels, and participants with sleep disordered breathing with normal CO2 regulation.
Participants will be recruited through outpatient clinics for sleep disordered breathing. The participants will undergo comprehensive breathing assessments on enrolment including an overnight sleep study. Participants will undergo further daytime breathing assessments before and after their bariatric surgery. End of study will be 6 months after surgery - participants will have a final comprehensive breathing assessment including an overnight sleep study to review resolution of their breathing changes. Depending on the wait list time for the bariatric surgery, it is anticipated that participants will be enrolled in the study for 2 years.
- Conditions
- Obesity Hypoventilation Syndrome (OHS)
- Being tested
- Bariatric Surgery
- Medical subject headings
- Obesity Hypoventilation Syndrome
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Bariatric SurgeryProcedure or surgery
Weight loss surgery with either gastric sleeve or gastric bypass surgery
| Study group | Role | What they receive |
|---|---|---|
| Hypercapnic | Obese patients with daytime hypercapnia Receives: Procedure: Bariatric Surgery | |
| Eucapnic | Obese patients with normal daytime carbon dioxide levels Receives: Procedure: Bariatric Surgery |
What is being measured
The primary outcome is the main question the study is designed to answer.
Expiratory flow limitation as measured by forced oscillation testing
Measurement of expiratory flow limitation at different position including upright, 45 degrees and supine. We will explore whether expiratory flow limitation can differentiate hypercapnic and eucapnic patients
Measured: Measurements on enrolment into study; measurements prior to bariatric surgery (once patients has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Degree of change in expiratory flow limitation
Explore whether the degree of positional change in expiratory flow limitation can differentiate between eucapnic and hypercapnic patients
Measured: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Secondary outcomes (27)
Closing capacity
Measurement of closing capacity at different position including upright, 45 degrees and supine. We will explore whether expiratory flow limitation can differentiate hypercapnic and eucapnic patients
Measured: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Degree of change in closing capacity
Explore whether the degree of positional change in closing capacity can differentiate between eucapnic and hypercapnic patients
Measured: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Correlation between closing capacity and expiratory flow limitation
Compare outcome 1 and 3 to explore whether there is a relationship between expiratory flow limitation and closing capacity
Measured: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Intra-abdominal pressure
We will measure intra-abdominal pressure and explore whether hypercapnic patients have increased intra-abdominal pressure. Positional changes will be measured
Measured: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Correlation between intra-abdominal pressure, closing capacity and expriatory flow limitation
Compare outcome 1,3 and 6. This is a complex multi-compartment model that can differentiate hypercapnia and eucapnic patients
Measured: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Upper airway collapsibility
Measurement of upper airway collapsibility as measure by negative expiratory pressure. Explore whether there is a relationship between hypercapnic and eucapnic patients depending on degree of upper airway collapsibility
Measured: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Lung compliance
Measurement of lung compliance with pressure volume curve including measurements in different positions (upright, 45 degrees and supine)
Measured: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Respiratory muscle strength (maximal inspiratory pressure/maximal expiratory)
Measurement of inspiratory and expiratory muscle strength
Measured: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Respiratory muscle strength (SNIP test)
Measurement of sniff nasal inspiratory pressure
Measured: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Daytime neural respiratory drive (para-sternal electromyography measurements)
Daytime neural respiratory drive as measured by parasternal electromyography (EMG) measurements can differentiate between hypercapnic and eucapnic patients
Measured: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Daytime neural respiratory drive (diaphragm electromyography measurements)
Daytime neural respiratory drive as measured by diaphragm electromyography (EMG) measurements can differentiate between hypercapnic and eucapnic patients
Measured: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Nocturnal neural respiratory drive (para-sternal electromyography measurements)
Nocturnal neural respiratory drive as measured by parasternal electromyography (EMG) measurements can differentiate between hypercapnic and eucapnic patients
Measured: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Nocturnal neural respiratory drive (diaphragm electromyography measurements)
Nocturnal neural respiratory drive as measured by diaphragm electromyography (EMG) measurements can differentiate between hypercapnic and eucapnic patients
Measured: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Quality of life post bariatric surgery with SF-36
Quality of life changes after bariatric surgery more than with standard medical therapy
Measured: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Quality of life post bariatric surgery with EQ-5D
Quality of life changes after bariatric surgery more than with standard medical therapy
Measured: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Symptom change after commencement of medical therapy compared to bariatric surgery measured with Epworth Sleepiness Scale
Symptom change after bariatric surgery is more than with standard medical therapy
Measured: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Symptom change after commencement of medical therapy compared to bariatric surgery measured with mMRC (modified medical research council) dypnoea score
Symptom change after bariatric surgery is more than with standard medical therapy
Measured: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Symptom change after commencement of medical therapy compared to bariatric surgery measured with Multi-dimensional dyspnoea profile
Symptom change after bariatric surgery is more than with standard medical therapy
Measured: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Symptom change after commencement of medical therapy compared to bariatric surgery measured with Severe Respiratory Insufficiency Questionnaire
Symptom change after bariatric surgery is more than with standard medical therapy
Measured: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Changes in healthcare resource usage in OHS patients post bariatric surgery
Estimation of healthcare usage cost in the 6 months prior to surgery and 6 months post surgery including medication costs and re-admissions to hospital
Measured: 6 months pre bariatric surgery and 6 months post bariatric surgery
Improvement in daytime CO2 levels
Arterial blood gas performed before and after bariatric surgery with improvement in CO2 levels
Measured: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Improvement in apnoea-hyponoea index
Patients will have diagnostic sleep study before and after bariatric surgery
Measured: Before bariatric surgery on enrolment and 6 months after bariatric surgery
Improvement in mean nocturnal oxygen saturation during sleep
Patients will have diagnostic sleep study before and after bariatric surgery
Measured: Before bariatric surgery on enrolment and 6 months after bariatric surgery
Improvement in mean time spent below 90% oxygen saturation during sleep
Patients will have diagnostic sleep study before and after bariatric surgery
Measured: Before bariatric surgery on enrolment and 6 months after bariatric surgery
Changes in sleep architecture measured by %slow wave sleep and %REM sleep
Patients will have diagnostic sleep study before and after bariatric surgery
Measured: Before bariatric surgery on enrolment and 6 months after bariatric surgery
Improvement in diaphragm function
Diaphragm thickening will be measured by ultrasound assessment
Measured: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Improvement in glycaemic control
HbA1C will be measured before and after bariatric surgery
Measured: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted19 Jul 2019
- Study start20 Jun 2019
- Primary completionJul 2024 (estimated)
- Study completionJul 2024 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Obesity Hypoventilation Syndrome (OHS)Studies of the same condition, open and under way.
- More trials run by Guy's and St Thomas' NHS Foundation TrustThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case-control
- Time perspective
- Prospective
- Enrolment
- 30 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Guy's and St Thomas' NHS Foundation Trust
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Joerg Steier, PhD, Principal investigator, Guy's and St Thomas NHS Trust
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04025528
- Sponsor's protocol ID
- 258045
- Acronym
- PHOEBI
- Status last verified
- Mar 2023
- First submitted
- 21 Jun 2019
- Last updated
- 23 Mar 2023
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 23 Mar 2023. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Pathophysiology of Hypoventilation in Obesity and Effects of Bariatric Intervention: PHOEBI Study
- ClinicalTrials.gov ID
- NCT04025528
- Acronym / sponsor ID
- PHOEBI / 258045
- Conditions
- Obesity Hypoventilation Syndrome (OHS)
- Study type
- Observational
- Recruitment status
- Unknown status
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- Guy's and St Thomas' NHS Foundation TrustUniversity, hospital or other
- Study start
- 20 Jun 2019 (actual)
- Primary completion
- Jul 2024 (estimated)
- Study completion
- Jul 2024 (estimated)
- First posted
- 19 Jul 2019 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Breathing is impacted by obesity. Early changes are characterised by significant breathing abnormalities during sleep (a condition called sleep disordered breathing, the most common of which is obstructive sleep apnoea). As the breathing changes worsen in severity, it may result in a rise in carbon dioxide levels during daytime causing a condition called obesity hypoventilation syndrome (OHS). The current treatment for obesity related breathing changes include supportive breathing therapy at night, optimisation of associated medical conditions and weight loss.
Weight management is an important part of obesity treatment. Weight loss strategies such as life-style modification do not always work. Weight loss surgery (bariatric surgery) has been shown to be an effective weight management intervention with long-term results. This study aims to understand breathing changes that occurs due to obesity and their resolution after weight loss surgery. The investigators are aiming to recruit participants with sleep disordered breathing who are currently awaiting bariatric surgery. In particular, the investigators are interested in comparing breathing changes in participants with OHS, who have abnormal regulation of their carbon dioxide levels, and participants with sleep disordered breathing with normal CO2 regulation.
Participants will be recruited through outpatient clinics for sleep disordered breathing. The participants will undergo comprehensive breathing assessments on enrolment including an overnight sleep study. Participants will undergo further daytime breathing assessments before and after their bariatric surgery. End of study will be 6 months after surgery - participants will have a final comprehensive breathing assessment including an overnight sleep study to review resolution of their breathing changes. Depending on the wait list time for the bariatric surgery, it is anticipated that participants will be enrolled in the study for 2 years.
Study design
- Observational model
- Case-control
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Hypercapnic | – | Procedure: Bariatric SurgeryObese patients with daytime hypercapnia |
| Eucapnic | – | Procedure: Bariatric SurgeryObese patients with normal daytime carbon dioxide levels |
Who may qualify
- Ages
- 18 to 80 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- Obese patients who are considering bariatric surgery intervention
Key inclusion criteria (4 listed)
- Patients 18 years or older
- BMI > 40
- Patients with significant sleep disordered breathing requiring treatment
- Patient is being assessed for bariatric surgery for either gastric sleeve or gastric bypass surgery
Key exclusion criteria (10 listed)
- Patients with decompensated hypercapnic respiratory failure (pH< 7.3)
- Chronic hypercapnic respiratory failure due to a cause other than obesity such as neuromuscular, chest wall or airway disease
- Unstable cardiac disease including coronary artery disease and heart failure
- Significant co-morbid psychiatric disease requiring anti-psychotic medications
- Chronic pain syndrome on high dose opioid medications
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Bariatric SurgeryWeight loss surgery with either gastric sleeve or gastric bypass surgery | Procedure or surgery | Eucapnic, Hypercapnic |
Primary outcome
Expiratory flow limitation as measured by forced oscillation testing
Time frame: Measurements on enrolment into study; measurements prior to bariatric surgery (once patients has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Measurement of expiratory flow limitation at different position including upright, 45 degrees and supine. We will explore whether expiratory flow limitation can differentiate hypercapnic and eucapnic patients
Degree of change in expiratory flow limitation
Time frame: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Explore whether the degree of positional change in expiratory flow limitation can differentiate between eucapnic and hypercapnic patients
27 secondary outcomes
Closing capacity
Time frame: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Degree of change in closing capacity
Time frame: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Correlation between closing capacity and expiratory flow limitation
Time frame: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Intra-abdominal pressure
Time frame: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Correlation between intra-abdominal pressure, closing capacity and expriatory flow limitation
Time frame: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Upper airway collapsibility
Time frame: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Lung compliance
Time frame: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Respiratory muscle strength (maximal inspiratory pressure/maximal expiratory)
Time frame: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Respiratory muscle strength (SNIP test)
Time frame: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Daytime neural respiratory drive (para-sternal electromyography measurements)
Time frame: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Daytime neural respiratory drive (diaphragm electromyography measurements)
Time frame: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Nocturnal neural respiratory drive (para-sternal electromyography measurements)
Time frame: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Nocturnal neural respiratory drive (diaphragm electromyography measurements)
Time frame: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Quality of life post bariatric surgery with SF-36
Time frame: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Quality of life post bariatric surgery with EQ-5D
Time frame: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Symptom change after commencement of medical therapy compared to bariatric surgery measured with Epworth Sleepiness Scale
Time frame: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Symptom change after commencement of medical therapy compared to bariatric surgery measured with mMRC (modified medical research council) dypnoea score
Time frame: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Symptom change after commencement of medical therapy compared to bariatric surgery measured with Multi-dimensional dyspnoea profile
Time frame: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Symptom change after commencement of medical therapy compared to bariatric surgery measured with Severe Respiratory Insufficiency Questionnaire
Time frame: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Changes in healthcare resource usage in OHS patients post bariatric surgery
Time frame: 6 months pre bariatric surgery and 6 months post bariatric surgery
Improvement in daytime CO2 levels
Time frame: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Improvement in apnoea-hyponoea index
Time frame: Before bariatric surgery on enrolment and 6 months after bariatric surgery
Improvement in mean nocturnal oxygen saturation during sleep
Time frame: Before bariatric surgery on enrolment and 6 months after bariatric surgery
Improvement in mean time spent below 90% oxygen saturation during sleep
Time frame: Before bariatric surgery on enrolment and 6 months after bariatric surgery
Changes in sleep architecture measured by %slow wave sleep and %REM sleep
Time frame: Before bariatric surgery on enrolment and 6 months after bariatric surgery
Improvement in diaphragm function
Time frame: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Improvement in glycaemic control
Time frame: Measurements on enrolment into study; measurements prior to bariatric surgery (once patient has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery
Results and safety
Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 23 Mar 2023.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Joerg Steier, PhD principal investigator
Guy's and St Thomas NHS Trust
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Obesity Hypoventilation Syndrome (OHS), run by Guy's and St Thomas' NHS Foundation Trust at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: status not confirmed, as of the sponsor's last update on 23 Mar 2023. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Results are not available in the source record.
How can a doctor refer a patient or contact the research team?
Contact Michael Cheng, MBBS (+44 02071888070, michael.cheng@gstt.nhs.uk), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Expiratory flow limitation as measured by forced oscillation testing (time frame: Measurements on enrolment into study; measurements prior to bariatric surgery (once patients has a surgery date); measurements 2-4 weeks after bariatric surgery; and end of study measurements 6 months after bariatric surgery). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 23 Mar 2023.