Entropy-based Physiological Signal Analysis in Patients With Obstructive Sleep Apnoea (EPPOSA)

February 9, 2026 updated by: Ime Umoabasi, King's College London

Entropy-Based Assessment of Physiological Signals in Obstructive Sleep Apnoea Patients Pre and Post Continuous Positive Airway Pressure Therapy: A Secondary Analysis of 3DPiPPIn Trial Data

This observational study is being undertaken as a part of a Master of Research (MRes) in Clinical Research programme.

Its goal is to learn about how continuous positive airway pressure (CPAP) therapy changes the complexity of body signals in adults with obstructive sleep apnoea (OSA). The main question it aims to answer is:

- How does the complexity of physiological signals (specifically oxygen saturation, heart rate variability, and airflow) change in adults with OSA from before to after three and six months of CPAP treatment?

It will use data from individuals who took part in an earlier trial, called 3DPiPPIn, which tested the use of 3D-printed, customised masks CPAP masks through sleep studies.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

The purpose of this MRes student study is primarily to examine how the entropy, or complexity as measured by entropy, of physiological signals changes in patients with obstructive sleep apnoea (OSA) in response to continuous positive airway pressure (CPAP) therapy.

It is a secondary analysis of data from 3DPiPPIn, a randomised control trial investigating the feasibility of using 3D-printing to develop customised masks for patients receiving positive airway pressure (PAP) therapy.

The hypothesis for this study is that entropy-based measures derived from physiological signals will exhibit changes following CPAP therapy, when compared to pre-therapy measures, reflecting the modulation and restoration of physiological systems that were previously disrupted by OSA.

Study Type

Observational

Enrollment (Estimated)

160

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 Locations

  • United Kingdom
      • London, United Kingdom, WC2R 2LS
        • King's College London
      • London, United Kingdom, NW2 2QG
        • Royal Free Hospital

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

Sampling Method

Non-Probability Sample

Study Population

PAP-naive adults with obstructive sleep apnea (OSA), identified from the Sleep and Ventilation Service at Royal Free London NHS Foundation Trust, who participated in the 3DPiPPIn randomised controlled trial.

Description

Inclusion Criteria:

  • Participation in the 3DPiPPIn trial
  • Completion of the 3DPiPPIn trial to its primary endpoint of six months
  • Availability of physiological signal data at baseline, three months, and six months
  • Provision of informed consent permitting the use of their data in future research

Exclusion Criteria:

  • Non-completion of the 3DPiPPIn trial to its primary endpoint of six months
  • Missing physiological signal data at baseline, three months, or six months
  • No consent for the use of their data in future research

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

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
3DPiPPIn Trial Participants
Participants were originally recruited to the 3DPiPPIn trial from the Sleep and Ventilation Service at Royal Free London NHS Foundation Trust. The cohort for this secondary analysis comprises adults with sleep-disordered breathing and an Apnoea-Hypopnoea Index (AHI) >15 events/hour who required but had never received PAP therapy, drawn from the trial participants who provided consent for their data to be used in future research.
Device: Continuous Positive Airway Pressure Therapy
The intervention of interest within this secondary analysis study is Continuous Positive Airway Pressure (CPAP) Therapy, a device-based treatment used to maintain airway patency in patients with sleep-disordered breathing. As a retrospective study, participant exposure to CPAP occured exclusively within the original 3DPiPPIn trial.
Other Names:
  • CPAP
  • PAP
  • CPAP Therapy
  • PAP Therapy
  • Positive Airway Pressure Therapy

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Change in oxygen saturation entropy from pre to six months post CPAP therapy
Time Frame: From baseline to six months post-initiation of CPAP therapy
From baseline to six months post-initiation of CPAP therapy
Change in heart rate variability entropy from pre to six months post CPAP therapy
Time Frame: From baseline to six months post-initiation of CPAP therapy
From baseline to six months post-initiation of CPAP therapy
Change in airflow entropy from pre to six months post CPAP therapy
Time Frame: From baseline to six months post-initiation of CPAP therapy
From baseline to six months post-initiation of CPAP therapy

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in oxygen saturation entropy from pre to three months post CPAP therapy
Time Frame: From baseline to three months post-initiation of CPAP therapy
From baseline to three months post-initiation of CPAP therapy
Change in heart rate variability entropy from pre to three months post CPAP therapy
Time Frame: From baseline to three months post-initiation of CPAP therapy
From baseline to three months post-initiation of CPAP therapy
Change in airflow entropy from pre to three months post CPAP therapy
Time Frame: From baseline to three months post-initiation of CPAP therapy
From baseline to three months post-initiation of CPAP therapy
Relationship between residual Apnoea-Hypopnoea Index and oxygen saturation entropy
Time Frame: From baseline to three and/or six months post-initiation of CPAP therapy
The Apnoea-Hypopnoea Index (AHI) is the total number of apnoea and hypopnoea events per hour of sleep. The minimum value is 0 events/hour, and there is no fixed maximum value. Higher scores indicate more severe sleep-disordered breathing (worse outcome).
From baseline to three and/or six months post-initiation of CPAP therapy
Relationship between residual Apnoea-Hypopnoea Index and heart rate variability entropy
Time Frame: From baseline to three and/or six months post-initiation of CPAP therapy
The Apnoea-Hypopnoea Index (AHI) is the total number of apnoea and hypopnoea events per hour of sleep. The minimum value is 0 events/hour, and there is no fixed maximum value. Higher scores indicate more severe sleep-disordered breathing (worse outcome).
From baseline to three and/or six months post-initiation of CPAP therapy
Relationship between residual Apnoea-Hypopnoea Index and airflow entropy
Time Frame: From baseline to three and/or six months post-initiation of CPAP therapy
The Apnoea-Hypopnoea Index (AHI) is the total number of apnoea and hypopnoea events per hour of sleep. The minimum value is 0 events/hour, and there is no fixed maximum value. Higher scores indicate more severe sleep-disordered breathing (worse outcome).
From baseline to three and/or six months post-initiation of CPAP therapy
Relationship between Epworth Sleepiness Scale scores and oxygen saturation entropy
Time Frame: From baseline to three and/or six months post-initiation of CPAP therapy
The Epworth Sleepiness Scale (ESS) is a self-administered questionnaire that measures daytime sleepiness. Scores range from 0 to 24, with higher scores indicating greater daytime sleepiness (worse outcome).
From baseline to three and/or six months post-initiation of CPAP therapy
Relationship between Epworth Sleepiness Scale scores and heart rate variability entropy
Time Frame: From baseline to three and/or six months post-initiation of CPAP therapy
The Epworth Sleepiness Scale (ESS) is a self-administered questionnaire that measures daytime sleepiness. Scores range from 0 to 24, with higher scores indicating greater daytime sleepiness (worse outcome).
From baseline to three and/or six months post-initiation of CPAP therapy
Relationship between Epworth Sleepiness Scale scores and airflow entropy
Time Frame: From baseline to three and/or six months post-initiation of CPAP therapy
The Epworth Sleepiness Scale (ESS) is a self-administered questionnaire that measures daytime sleepiness. Scores range from 0 to 24, with higher scores indicating greater daytime sleepiness (worse outcome).
From baseline to three and/or six months post-initiation of CPAP therapy

Collaborators and Investigators

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

Sponsor

King's College London

Collaborators

Royal Free Hospital NHS Foundation Trust

Investigators

  • Study Director: Izaak Neri, King's College London
  • Study Director: Stephanie K Mansell, Royal Free London NHS Foundation Trust, University College London

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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)

April 1, 2026

Primary Completion (Estimated)

July 1, 2026

Study Completion (Estimated)

September 1, 2026

Study Registration Dates

First Submitted

January 29, 2026

First Submitted That Met QC Criteria

February 9, 2026

First Posted (Actual)

February 12, 2026

Study Record Updates

Last Update Posted (Actual)

February 12, 2026

Last Update Submitted That Met QC Criteria

February 9, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 366646

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

The data used in this secondary analysis include potentially re-identifiable patient information. In line with the open access approach of the study's parent trial, 3DPiPPIn, individual participant data will not be shared to protect participant confidentiality.

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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