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NCT Number: NCT05903001

Diaphragmatic Function as a Biomarker

Dyspnea is among the most common symptoms in patients with respiratory diseases such as Asthma, chronic obstructive pulmonary disease (COPD), Fibrosis, and Pulmonary Hypertension. However, the pathophysiology and underlying mechanisms of dyspnea in patients with respiratory diseases are still poorly understood. Diaphragm dysfunction might be highly prevalent in patients with dyspnea and respiratory diseases. The association of diaphragm function and potential prognostic significance in patients with respiratory diseases has not yet been investigated.

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Key information

Conditions

Dyspnea; Asthmatic Asthma Bronchial Diseases COPD Cardiovascular Diseases Chronic Disease Disease Attributes Dyspnea Fibrosis Hypersensitivity Hypersensitivity, Immediate Hypertension Hypertension, Pulmonary Immune System Diseases Lung Diseases Lung Diseases, Obstructive Pathologic Processes Pathological Conditions, Signs and Symptoms Pulmonary Disease, Chronic Obstructive Pulmonary Hypertension Respiration Disorders Respiratory Hypersensitivity Respiratory Tract Diseases Signs and Symptoms Signs and Symptoms, Respiratory Vascular Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

About this study

The aim of the present project is to comprehensively measure respiratory muscle function and strength in patients with respiratory diseases. The investigators attempt to recruit 800 patients across four disease groups (Asthma, COPD, Fibrosis, and Pulmonary Hypertension) and the investigators intend to measure diaphragm and accessory respiratory muscle function and strength, lung function, and exercise tolerance, as well as the participants' symptom burden during one day at baseline in the investigators' lab. Thereafter, the investigators will follow up on patients by phone 3 months, 6 months, 12 months and 18 months after the investigators have seen them in the investigators' lab. In a small subset of patients (50 overall at most) and in those in whom a recently approved drug based therapy has been initiated (i.e. Sotatercept in PH, Nintedanib in ILD, Brensocatib in Bronchiectasis, Dupilumab in COPD, Anti IL-4/IL 13 or Anti IL 5 antibodies in eosinophilic asthma) follow up will not be by phone only but also in person to repeat the above mentioned non-invasive measurements. Based on these results, not only the association between dyspnea exercise tolerance and diaphragm function in patients with respiratory diseases can be assessed, but also the prognostic significance of diaphragm dysfunction in these patients can be determined. As such, hospitalization and exacerbation requiring the intake of steroids will be assessed and followed up on by phone, and therefore the prognostic significance of diaphragm dysfunction in predicting hospitalization and the intake of steroids can be determined.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • patient has one of the following lung diseases: COPD, bronchial asthma, pulmonary fibrosis, pulmonary hypertension
  • is 18 years or older
  • is mentally and physically able to understand the study and to follow instructions
  • are legally competent
  • signed declaration of consent

Exclusion criteria

  • BMI > 35
  • current or treatments or diseases in the past which could influence the evaluation of the study
  • Expected lack of willingness to actively participate in study-related measures
  • alcohol or drug abuse
  • disc herniation/prolapse
  • epilepsy
  • wheelchair bound
  • in custody due to an official or court order
  • in a dependent relationship or employment relationship with investigating physician or one of their deputy
  • emergency inpatient hospital stay within 4 weeks before study-specific examinations

Treatment and study plan

Diaphragm Ultrasound

Diagnostic Test

Ultrasound of the Diaphragm at the end of inspiration and expiration

Intercostal Muscle Ultrasound

Diagnostic Test

Ultrasound of the Intercostal Muscles at the end of inspiration and expiration

Borg scale

Diagnostic Test

Questionnaire for Perceived Exertion (Borg Rating of Perceived Exertion Scale)

MRC Breathlessness Scale

Diagnostic Test

The MRC Dyspnoea Scale allows the patients to indicate the extent to which their breathlessness affects their mobility.

Respiratory Questionaire

Diagnostic Test

Specialized respiratory questionnaire with different domains (Emotional Domain, Dyspnea Domain, Mastery Domain, Fatigue Domain)

GINA classification of Asthma

Diagnostic Test

Patients are classified according to the GINA classification of Asthma.

Measurement of respiratory mouth pressure

Diagnostic Test

Inspiratory and expiratory Measurement of respiratory mouth pressure

SNIP

Diagnostic Test

Measurement of Sniff Nasal Inspiratory Pressure

6-minute walking distance

Diagnostic Test

The maximum walking distance achieved in 6 minutes

60 seconds sit-to-stand test

Diagnostic Test

number of repetitions achieved in sitting down and standing up in 60 seconds

Electromyography

Diagnostic Test

electromyography of the muscles of respiration via superficial electrodes

Lung function

Diagnostic Test

Measurement of lung function via body plethysmography

CAT-Questionnaire

Diagnostic Test

COPD Assessment Test (CAT)

European Society of Cardiology (ESC)/ European Respiratory Society (ERS) risk group

Diagnostic Test

Patients with pulmonary hypertension are classified according to the ESC/ERS risk group.

Primary outcomes

  1. Dyspnea Borg scale 1 to 10

    Time frame: 6 months recruiting

    Borg scale before and after "6 minute walking distance" test. Lower scores show fewer dyspnea, higher scores indicate more dyspnea.

  2. Dyspnea Borg scale 1 to 10

    Time frame: follow up 3 months after recruitment

    Borg scale before and after "6 minute walking distance" test. Lower scores show fewer dyspnea, higher scores indicate more dyspnea.

  3. Dyspnea Borg scale 1 to 10

    Time frame: follow up 6 months after recruitment

    Borg scale before and after "6 minute walking distance" test. Lower scores show fewer dyspnea, higher scores indicate more dyspnea.

  4. Dyspnea Borg scale 1 to 10

    Time frame: follow up 12 months after recruitment

    Borg scale before and after "6 minute walking distance" test. Lower scores show fewer dyspnea, higher scores indicate more dyspnea.

  5. Dyspnea Borg scale 1 to 10

    Time frame: follow up 18 months after recruitment

    Borg scale before and after "6 minute walking distance" test. Lower scores show fewer dyspnea, higher scores indicate more dyspnea.

Secondary outcomes

  1. 6 minute walking distance in m

    Time frame: 6 months recruiting

    Measurement of achieved walking distance in 6 minutes

  2. Sit-to stand-test (60 seconds)

    Time frame: 6 months recruiting

    Measurement of achieved repetitions of standing up and sitting down from an initial seated position in 60 seconds.

  3. New York Heart Association (NYHA) classification scale 1 to 4

    Time frame: 6 months recruiting, follow up up to 18 months after last recruitment

    Patients are linked to a NYHA degree. Lower scores show fewer dyspnea, higher scores indicate more dyspnea.

  4. Modified Medical Research Council (MRC) Breathlessness Scale 1 to 5

    Time frame: 6 months recruiting, follow up up to 18 months after last recruitment

    Patients are assessed and grouped according to their MRC Breathlessness Scale. Lower scores show fewer dyspnea, higher scores indicate more dyspnea.

  5. Chronic Respiratory Questionnaire (CRQ)

    Time frame: 6 months recruiting, follow up up to 18 months after last recruitment

    Assessments of different domains (Emotional Domain, Dyspnea Domain, Mastery Domain, Fatigue Domain) in a standardized questionnaire on a scale from 1 to 7. The scores for each question of each dimension are added together and divided by the number of completed questions in each domain. In general, higher scores mean a worse outcome and lower scores mean a better outcome.

    For the dyspnea domain for example, a high score means that patients have less dyspnea, and a low score means that patients have more dyspnea.

  6. COPD Assessment Test (CAT-Questionnaire) from 0 to 40 points.

    Time frame: 6 months recruiting, follow up up to 18 months after last recruitment

    Patients are evaluated and placed into the corresponding groups. Lower scores show fewer dyspnea, higher scores indicate more dyspnea.

  7. Global Initiative for Asthma (GINA) classification

    Time frame: 6 months recruiting, follow up up to 18 months after last recruitment

    Patients are assessed and grouped as mild, moderate, or severe according to the GINA classification.

  8. Body Plethysmography

    Time frame: 6 months recruiting

    TLC (Total lung capacity) in percent predicted.

  9. Diaphragm Thickening Ratio (DTR) in percent

    Time frame: 6 months recruiting

    Via ultrasound, the diaphragm thickening ratio (DTR) was calculated as thickness at total lung capacity (TLC) divided by thickness at functional residual capacity (FRC).

  10. Diaphragm thickness at Total lung capacity (TLC)

    Time frame: 6 months recruiting

    Via ultrasound, the diaphragm thickness at TLC is measured at the maximum point of inspiration.

  11. Diaphragm thickness at functional capacity (FRC)

    Time frame: 6 months recruiting

    Via ultrasound, the diaphragm thickness at FRC is measured after a normal expiration.

  12. Diaphragm ultrasound sniff velocity in cm/s

    Time frame: 6 months recruiting

    Via ultrasound, the diaphragm sniff velocity was assessed during tidal breathing and following a maximum sniff.

  13. Intercostal Muscle ultrasound thickness at Total lung capacity (TLC) in cm

    Time frame: 6 months recruiting

    Via ultrasound, the intercostal thickness at TLC is measured at the maximum point of inspiration.

  14. Intercostal Muscle ultrasound thickness at functional capacity (FRC) in cm

    Time frame: 6 months recruiting

    Via ultrasound, the intercostal thickness at FRC is measured after a normal expiration.

  15. Intercostal Muscle Thickening Ratio in percent

    Time frame: 6 months recruiting

    Via ultrasound, the intercostal muscle thickening ratio was calculated as thickness at total lung capacity (TLC) divided by thickness at functional residual capacity (FRC).

  16. Maximum Inspiratory Pressure (MIP) in percent predicted

    Time frame: 6 months recruiting

    Measurement of Maximum Inspiratory Pressure

  17. Maximum Expiratory Pressure (MEP) in percent predicted

    Time frame: 6 months recruiting

    Measurement of Maximum Expiratory Pressure

  18. Sniff Nasal Inspiratory Pressure (SNIP) in percent predicted

    Time frame: 6 months recruiting

    Measurement of Sniff Nasal Inspiratory Pressure

  19. Blood Gas Analysis in cmH2O

    Time frame: 6 months recruiting

    oxygen partial pressure (pO2)

  20. Blood Gas Analysis in cmH2O

    Time frame: 6 months recruiting

    carbon dioxide partial pressure (pCO2)

  21. Blood Gas Analysis

    Time frame: 6 months recruiting

    pH scale

  22. Blood Gas Analysis in mmol/l

    Time frame: 6 months recruiting

    Base Excess

  23. Blood Gas Analysis in (I1/s) percent

    Time frame: 6 months recruiting

    Base Excess

  24. Electromyography (EMG)

    Time frame: 6 months recruiting

    Measurement of electrical activity during different breathing maneuvers (Sniff, Cough, Valsalva, Mueller) via superficial electrodes placed on the diaphragm and accessory respiratory muscles (Sternocleidomastoideus muscle, intercostal muscles).

Study contacts

Contact information is provided by the study sponsor or research team.

Jens Spiesshoefer, MD

CONTACT

[email protected]

0049 2418037036

Sponsors and collaborators

Lead sponsor

RWTH Aachen University

Other

Registry information

Official study title

Diaphragmatic Function as a Biomarker in Patients With Respiratory Diseases

Acronym: DFUNBIO

Important dates

Study start
2023
Primary completion
2026
Study completion
2026
First posted
Jun 15, 2023
Registry last updated
Jan 28, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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