The Cardiovascular Consequences of Sleep Apnea Plus COPD (Overlap Syndrome)

The Cardiovascular Consequences of Sleep Apnea Plus COPD (Overlap Syndrome) (NCT05237505) is a Phase 2 interventional studying Obstructive Sleep Apnea and Chronic Obstructive Pulmonary Disease, sponsored by University of California, San Diego. RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.

About This Trial

Major progress has been made in the area of cardiovascular disease, but we believe that further progress will involve mechanistically addressing underlying respiratory causes including chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA). The most common cause of death in COPD is cardiovascular, although mechanisms are unknown. OSA has been associated with major neurocognitive and cardiovascular sequelae, the latter likely a function of autonomic nervous system abnormalities, oxidative stress, inflammation, and other pathways. Recent data suggest that individuals with OVS die preferentially of cardiovascular disease compared to OSA or COPD alone, although mechanisms are again unclear. The combination of OSA and COPD may lead to profound hypoxemia. Individuals with COPD can develop pulmonary hypertension via disturbances in gas exchange and parenchymal injury leading to loss of pulmonary vasculature. OSA has been associated with mild to moderate pulmonary hypertension, but the situation may be worse if combined with parenchymal lung disease. The biological response to sustained hypoxemia has been carefully studied as has the topic of intermittent hypoxemia; however, to our knowledge, very little research has occurred regarding the combination of sustained plus intermittent hypoxia as seen in OVS. For example, we do not really know whether individuals with OVS develop coronary disease, right or left heart failure, dysrhythmias or some combination of abnormalities predisposing them to cardiovascular death. Thus, design of interventional studies is challenging as causal pathways are poorly understood despite our considerable preliminary data addressing these issues. The purpose of this study is to examine vascular mechanisms in individuals with COPD/OSA overlap syndrome (OVS) compared with matched individuals with obstructive sleep apnea (OSA) alone or chronic obstructive pulmonary disease (COPD) alone and to perform a phase II pilot mechanistic clinical trial in OVS to examine the effect size of nocturnal bi-level positive airway pressure (PAP) vs. nocturnal oxygen therapy in cardiovascular outcomes.

What Stage of Research Is This?

Phase 2 trials evaluate whether a treatment actually works against Obstructive Sleep Apnea and continue monitoring side effects. Phase 2 enrolls larger groups (typically 100–300 patients) and produces the first real efficacy signal. A successful Phase 2 readout is what unlocks the much larger Phase 3 confirmatory trials needed for FDA approval.

This trial is currently recruiting participants. The sponsor has registered the study with ClinicalTrials.gov as actively enrolling, which means new applicants who meet the eligibility criteria can be considered for screening. Trial status can change between updates — confirm current recruiting status with the study contact before traveling for a screening visit.

Target enrollment of 240 participants puts this in the typical range for a Phase 2-style efficacy study or a moderate Phase 3 trial in a focused Obstructive Sleep Apnea subpopulation. At this scale, the study has enough statistical power to detect a clear treatment effect but is not the largest cohort in the field.

Who May Be Eligible (Plain English)

Who May Qualify: - Provision of signed and dated willing to sign a consent form form. - Stated willingness to comply with all study procedures and availability for the duration of the study. - Persons aged 40-79. - For women, only postmenopausal women will be included - Diagnosed with untreated moderate to severe obstructive sleep apnea (apnea-hypopnea index ≥15 events/hr and ≤80 events/hr) and/or diagnosed with COPD with FEV1/FVC ratio \<0.7 and will be on stable medications as assessed by a board-certified pulmonologist. Who Should NOT Join This Trial: - Premenopausal women (i.e. women are pregnant or may become pregnant) or lactation - Presence of specific devices: cardiac implantable electronic device (CIED) such as pacemakers, implantable cardioverter defibrillators (ICDs) and cardiac resynchronization therapy (CRT) devices, metallic foreign bodies, implantable neurostimulation systems, cochlear implants/ear implant, drug infusion pumps (insulin delivery, analgesic drugs, or chemotherapy pumps), metallic fragments such as bullets, shotgun pellets, and metal shrapnel , cerebral artery aneurysm clips, magnetic dental implants, and artificial limb. - Known allergic reactions to components of the study intervention: (if getting contrast, MRI contrast (gadolinium)). - Concurrent severe sleep disorders (such as periodic limb movements, restless legs syndrome, narcolepsy, idiopathic hypersomnia, etc). - Exhibit Cheyne-Stokes respiration or central sleep apnea (\> 25 % of events central) - Take potentially confounding medications or hormones that affect breathing. - Subjects will be excluded if they are deemed medically unstable with active neurological, cardiac, liver, endocrine, and infectious diseases. - We will also exclude participants with pulmonary disease apart from COPD. - We will exclude participants with active cancer treatment. ...See full criteria on ClinicalTrials.gov Always talk to your doctor about whether this trial is right for you.

These are translations of the protocol\'s inclusion and exclusion criteria, simplified for patients and caregivers. The original clinical text appears below. Eligibility is ultimately confirmed by the trial site\'s screening process — this summary is a starting point for a conversation with your doctor, not a final determination.

Original Eligibility Criteria

View original clinical language

Inclusion Criteria: * Provision of signed and dated informed consent form. * Stated willingness to comply with all study procedures and availability for the duration of the study. * Persons aged 40-79. * For women, only postmenopausal women will be included * Diagnosed with untreated moderate to severe obstructive sleep apnea (apnea-hypopnea index ≥15 events/hr and ≤80 events/hr) and/or diagnosed with COPD with FEV1/FVC ratio \<0.7 and will be on stable medications as assessed by a board-certified pulmonologist. Exclusion Criteria: * Premenopausal women (i.e. women are pregnant or may become pregnant) or lactation * Presence of specific devices: cardiac implantable electronic device (CIED) such as pacemakers, implantable cardioverter defibrillators (ICDs) and cardiac resynchronization therapy (CRT) devices, metallic foreign bodies, implantable neurostimulation systems, cochlear implants/ear implant, drug infusion pumps (insulin delivery, analgesic drugs, or chemotherapy pumps), metallic fragments such as bullets, shotgun pellets, and metal shrapnel , cerebral artery aneurysm clips, magnetic dental implants, and artificial limb. * Known allergic reactions to components of the study intervention: (if getting contrast, MRI contrast (gadolinium)). * Concurrent severe sleep disorders (such as periodic limb movements, restless legs syndrome, narcolepsy, idiopathic hypersomnia, etc). * Exhibit Cheyne-Stokes respiration or central sleep apnea (\> 25 % of events central) * Take potentially confounding medications or hormones that affect breathing. * Subjects will be excluded if they are deemed medically unstable with active neurological, cardiac, liver, endocrine, and infectious diseases. * We will also exclude participants with pulmonary disease apart from COPD. * We will exclude participants with active cancer treatment. * We will exclude azotemia (estimated glomerular fraction rate \< 30ml/min) as there is some concern about giving gadolinium to these patients (if getting contrast MRI). * people with exposures deemed to be problematic for the research e.g. any smoking in bedroom by participant or household member, major second-hand smoke, e-cigarettes, tetrahydrocannabinol, major drug or alcohol consumption (\>3 oz/day) and other environmental pollution effects (indoor and outdoor). * Individuals who are already on continuous O2 for COPD or PAP treatment for OSA. * Patients with sustained desaturations below 89% during wake time will be excluded for ethical reasons since withholding oxygen in hypoxemic patients would be at odds with standard of care. * Individuals with OSA (AHI range 15-80/hr) will be screened for pathological sleepiness and will be excluded if ESS \>18/24, history of motor vehicle accident or near miss accident, or high-risk occupation. * COPD individuals with arterial PCO2 higher than 52 mmHg will be excluded. * Individuals who are currently incarcerated.

Treatments Being Tested

DEVICE

bi-level positive pressure non invasive ventilation

Participants randomized to the bi-level arm will be provided with an auto bi-level device that automatically delivers the required pressure. The settings in the auto bi-level will be minimum EPAP of 4 cmH2O, maximum IPAP of 24 cmH2O, and a range of pressure support between 6-10 cmH2O. For those participants who have been randomized to the bi-level group but have not successfully acclimated to the device with the automatic bi-level settings, we will conduct an in-lab titration of the bi-level therapy during the optional Overnight visit 2.

DRUG

Oxygen gas

The dose of nocturnal oxygen in all participants in the oxygen therapy arm will be 2 liters/minute. Patients with daytime hypoxemia, measured as sustained desaturations below 89% during wake time and/or arterial blood PO2 ≤ 55 mmHg, will be excluded from this study (as specified in the exclusion criteria) for ethical reasons since withholding oxygen in hypoxemic patients would be at odds with standard of care.

Locations (1)

Trial sites listed on ClinicalTrials.gov for this study. Site activation status can vary — confirm with the specific site before traveling for a screening visit.

UCSD Sleep Research

La Jolla, California, United States

How to Talk to Your Doctor About This Trial

Bring the printable summary of this trial — including the NCT ID (NCT05237505), the sponsor (University of California, San Diego), and the key eligibility criteria — to your next appointment. Your doctor can review the inclusion and exclusion criteria against your medical history, lab values, and current treatments to assess whether you are likely to qualify. They can also help you weigh whether trial participation makes sense alongside your existing care plan.

Useful questions to walk through together: What does the trial protocol require beyond standard care? How long is the active treatment phase, and how long is follow-up? Are there study visits at sites I can reach? Who pays for the trial-specific procedures, and who pays for standard-of-care portions? See our 25 questions to ask about clinical trials guide for a more complete checklist.

Authoritative Sources

The official record for this trial lives on ClinicalTrials.gov — the federal registry maintained by the National Library of Medicine at NIH. For background on how this trial fits into the FDA approval pathway, see the FDA drug approval process. For oncology-specific guidance for patients considering trials, the National Cancer Institute publishes patient-oriented overviews. International trial registries are aggregated by the WHO ICTRP.

Frequently Asked Questions

What is the NCT05237505 clinical trial studying?

Who can participate in NCT05237505?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

How do I contact the trial site for NCT05237505?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

How This Page Is Built

Every field on this page is pulled directly from the ClinicalTrials.gov API v2 — no estimates, no proxies. The plain-English eligibility translation is generated from the original protocol text and reviewed for fidelity to the underlying clinical criteria. The original clinical text remains visible in the collapsible section above so users and clinicians can verify the translation. Read the full methodology for the data pipeline and known limitations.

Source: ClinicalTrials.gov API v2 record for NCT05237505. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT05237505. Data: ClinicalTrials.gov."

Medical disclaimer: This page is informational, not medical advice. Talk to your doctor about whether a clinical trial is right for you.

Last updated 2026-05-08 · Data from ClinicalTrials.gov.