Hypercapnic Burden in Adults With Obesity Undergoing Diagnostic Polysomnography for Suspected Obstructive Sleep Apnea (HBO-POSA)

September 7, 2026 updated by: Hospices Civils de Lyon

Hypercapnic Burden in Adults With Obesity Undergoing Diagnostic Polysomnography for Suspected Obstructive Sleep Apnea: A Prospective Observational Cohort Study

Obesity-related sleep hypoventilation represents a continuum ranging from isolated nocturnal hypoventilation to obesity hypoventilation syndrome. Current diagnostic criteria rely mainly on dichotomous thresholds and may not adequately reflect cumulative nocturnal carbon dioxide exposure.

Hypercapnic burden, defined as the cumulative area under the transcutaneous carbon dioxide (PtcCO₂) curve above a predefined threshold, has recently emerged as a novel physiological marker integrating both the intensity and duration of nocturnal hypercapnia.

This prospective observational cohort study aims to evaluate the association between nocturnal hypercapnic burden and obstructive sleep apnea severity, assessed by the apnea-hypopnea index (AHI), in adults with obesity referred for diagnostic polysomnography.

Secondary objectives include evaluating associations between hypercapnic burden and sleep architecture, respiratory events, oxygenation parameters, daytime symptoms, and patient-reported outcomes. In addition, the study will investigate the relationship between nocturnal hypercapnic burden and sleep inertia, assessed using the Sleep Inertia Questionnaire (SIQ), based on the hypothesis that greater nocturnal carbon dioxide exposure immediately before awakening may contribute to impaired alertness upon awakening.

Hypothesis: Increased nocturnal hypercapnic burden is associated with greater obstructive sleep apnea severity and reflects an additional physiological dimension of obesity-related sleep hypoventilation beyond conventional polysomnographic indices. Furthermore, higher nocturnal hypercapnic burden is hypothesized to be associated with greater sleep inertia.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

150

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • France
      • Lyon, France, 69004
        • Croix-Rousse Hospital, Hospices Civils de Lyon
        • Contact:
        • Principal Investigator:
          • Virginie INFANTI, Dr

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age ≥18 years.
  • Body mass index (BMI) ≥30 kg/m².
  • Referred to the Sleep Medicine Center for routine diagnostic polysomnography because of suspected obstructive sleep apnea.
  • Affiliated with a French health insurance scheme.
  • Received information about the study and did not object to the use of their data.
  • Able to understand the study information and complete study questionnaires.

Exclusion Criteria:

  • Legal incapacity or inability to provide non-opposition to participation.
  • Previous treatment with continuous positive airway pressure (CPAP) or non-invasive ventilation.
  • Participation in another interventional clinical study that could interfere with the present study.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Diagnostic
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Adults with obesity referred for diagnostic polysomnography
Adults with obesity (body mass index ≥30 kg/m²) referred to the Sleep Medicine Center for routine diagnostic polysomnography because of suspected obstructive sleep apnea
Behavioral: Sleep Inertia Questionnaire (SIQ)
The only research-specific procedure is the completion of the Sleep Inertia Questionnaire (SIQ), a self-administered questionnaire requiring approximately 5 minutes to complete and performed once after the diagnostic sleep study.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Correlation between nocturnal hypercapnic burden and apnea-hypopnea index
Time Frame: Baseline only (overnight diagnostic polysomnography)

Correlation between nocturnal hypercapnic burden above 45 mmHg (HB45), defined as the area under the nocturnal transcutaneous carbon dioxide pressure (PtcCO₂) curve above 45 mmHg and normalized per hour of recording (mmHg·min/hour), and the apnea-hypopnea index derived from diagnostic polysomnography (events/hour).

The correlation will be assessed using Pearson's or Spearman's correlation coefficient, according to data distribution.
Baseline only (overnight diagnostic polysomnography)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Hospices Civils de Lyon

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

November 1, 2026

Primary Completion (Estimated)

November 3, 2028

Study Completion (Estimated)

November 3, 2028

Study Registration Dates

First Submitted

August 11, 2026

First Submitted That Met QC Criteria

September 7, 2026

First Posted (Actual)

September 9, 2026

Study Record Updates

Last Update Posted (Actual)

September 9, 2026

Last Update Submitted That Met QC Criteria

September 7, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 69HCL26_0743
  • ID RCB (Other Identifier: 2026-A01760-51)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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