The Potential Added Value of Impulse Oscillometry in Asthma Monitoring (AM-IOS)

September 8, 2025 updated by: Universitair Ziekenhuis Brussel

The goal of this longitudinal observational study is to learn if impulse oscillometry (IOS) has an added value in asthma monitoring in adult asthma patients who are prescribed a change in asthma maintenance therapy. The main questions it aims to answer are:

  • Is there a difference in the change in IOS parameters and FEV1 respectively, stratified according to change in asthma control test?
  • Is there a difference in the change in IOS parameters and FEV1 respectively, stratified according to change in other questionnaire such as the asthma control questionnaire and the asthma quality of life questionnaire.
  • Are the proposed minimal clinically important differences (MCIDs) valid for short follow-up periods (3 - 6 months)?

Participants will undergo lung function testing (full lung function, multiple breath nitrogen washout, impulse oscillometry) and questionnaires (asthma control test, asthma control questionnaire, asthma quality of life questionnaire), once during the baseline visit and once during the follow-up visit three to six months later.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

50

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 Locations

  • Belgium
      • Brussels, Belgium, 1090
        • Recruiting
        • Universitair Ziekenhuis Brussel

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:

  • Adult asthma patients with a scheduled consultation at the outpatient hospital to whom a step-up or step-down of their pharmacological asthma treatment is prescribed

Exclusion Criteria:

  • Unstable asthma (defined as need for oral corticosteroids or (respiratory) antibiotic course in the 4 weeks before inclusion or any major medical issue in the 4 weeks before inclusion)

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Adult asthma patients
Lung function tests (full lung function, multiple breath nitrogen washout, impulse oscillometry) and questionaires (asthma control test, asthma control questionnaire, asthma quality of life questionnaire) will be conducted, once at baseline and once 3 - 6 months later during follow-up.
Other: Full lung function
This includes spirometry, body plethysmography and single breath gas transfer test. These are all non-invasive physiological measurements / lung function tests. Measures flow volumes, lung volumes and gas transfer respectively.
Other: Multiple breath nitrogen washout
Non-invasive physiological measurement / lung function test. 100% oxygen is inhaled and the nitrogen concentration in the lungs is measured. This test gives information on the ventilation distribution in the lungs.
Other: Impulse oscillometry
Non-invasive physiological measurement / lung function test. This technique superimposes sound waves on tidal breathing. The patient can breathe normally trough the device, no forced respiratory maneuvers are required. It gives information on the reactance and resistance of the lung.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in frequency dependance of resistance (FDR) stratified according to change in asthma control test (ACT)
Time Frame: Once at baseline and 3 - 6 months later during follow-up
Frequency dependance of resistance (FDR) is an impulse oscillometry parameter. FDR is expressed in kPa/(L.s). A lower FDR indicates a clinically better outcome. The ACT is a questionnaire which consists of 5 questions, each evaluated on a 5-point Likert-Scale. Total score ranges between 5 and 25, where a lower score is clinically worse than a higher score.
Once at baseline and 3 - 6 months later during follow-up
Change in area of reactance (AX) stratified according to change in asthma control test (ACT)
Time Frame: Once at baseline and 3 - 6 months later during follow-up
Area of reactance (AX) is an impulse oscillometry parameter. AX is expressed in kPa/L. A lower AX indicates a clinically better outcome. The ACT is a questionnaire which consists of 5 questions, each evaluated on a 5-point Likert-Scale. Total score ranges between 5 and 25, where a lower score is clinically worse than a higher score.
Once at baseline and 3 - 6 months later during follow-up
Change in forced expiratory volume in 1 second (FEV1) stratified according to change in asthma control test (ACT)
Time Frame: Once at baseline and 3 - 6 months later during follow-up
Spirometry parameter: forced expiratory volume in 1 second (FEV1). FEV1 is expressed in L. A higher FEV1 indicates a clinically better outcome. The ACT is a questionnaire which consists of 5 questions, each evaluated on a 5-point Likert-Scale. Total score ranges between 5 and 25, where a lower score is clinically worse than a higher score.
Once at baseline and 3 - 6 months later during follow-up

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in frequency dependence of resistance (FDR) stratified according to change in asthma control questionnaire (ACQ-6)
Time Frame: Once at baseline and 3 - 6 months later during follow-up
Frequency dependance of resistance (FDR) is an impulse oscillometry parameter. FDR is expressed in kPa/(L.s). A lower FDR indicates a clinically better outcome. The ACQ-6 is a questionnaire which consists of 6 questions, each evaluated on a 7-point Likert-Scale. The total score score is divided by 6 yielding a mean score ranging from 0.0 to 6.0, where a lower score is clinically better than a higher score.
Once at baseline and 3 - 6 months later during follow-up
Change in area of reactance (AX) stratified according to change in asthma control questionnaire (ACQ-6)
Time Frame: Once at baseline and 3 - 6 months later during follow-up
Area of reactance (AX) is an impulse oscillometry parameter. AX is expressed in kPa/L. A lower AX indicates a clinically better outcome. The ACQ-6 is a questionnaire which consists of 6 questions, each evaluated on a 7-point Likert-Scale. The total score score is divided by 6 yielding a mean score ranging from 0.0 to 6.0, where a lower score is clinically better than a higher score.
Once at baseline and 3 - 6 months later during follow-up
Change in forced expiratory volume in 1 second (FEV1) stratified according to change in asthma control questionnaire (ACQ-6)
Time Frame: Once at baseline and 3 - 6 months later during follow-up
Spirometry parameter: forced expiratory volume in 1 second (FEV1). FEV1 is expressed in L. A higher FEV1 indicates a clinically better outcome. The ACQ-6 is a questionnaire which consists of 6 questions, each evaluated on a 7-point Likert-Scale. The total score score is divided by 6 yielding a mean score ranging from 0.0 to 6.0, where a lower score is clinically better than a higher score.
Once at baseline and 3 - 6 months later during follow-up
Change in frequency dependence of resistance (FDR) stratified according to change in asthma quality of life questionnaire (AQLQ)
Time Frame: Once at baseline and 3 - 6 months later during follow-up
Frequency dependance of resistance (FDR) is an impulse oscillometry parameter. FDR is expressed in kPa/(L.s). A lower FDR indicates a clinically better outcome. The AQLQ is a questionnaire which consists of 32 questions, each evaluated on a 7-point Likert-Scale. The total score is divided by 32 yielding a mean score ranging from 1.0 to 7.0, where a lower score is clinically worse than a higher score.
Once at baseline and 3 - 6 months later during follow-up
Change in area of reactance (AX) stratified according to change in asthma quality of life questionnaire (AQLQ)
Time Frame: Once at baseline and 3 - 6 months later during follow-up
Area of reactance (AX) is an impulse oscillometry parameter. AX is expressed in kPa/L. A lower AX indicates a clinically better outcome.The AQLQ is a questionnaire which consists of 32 questions, each evaluated on a 7-point Likert-Scale. The total score is divided by 32 yielding a mean score ranging from 1.0 to 7.0, where a lower score is clinically worse than a higher score.
Once at baseline and 3 - 6 months later during follow-up
Change in forced expiratory volume in 1 second (FEV1) stratified according to change in asthma quality of life questionnaire (AQLQ)
Time Frame: Once at baseline and 3 - 6 months later during follow-up
Spirometry parameter: forced expiratory volume in 1 second (FEV1). FEV1 is expressed in L. A higher FEV1 indicates a clinically better outcome.The AQLQ is a questionnaire which consists of 32 questions, each evaluated on a 7-point Likert-Scale. The total score is divided by 32 yielding a mean score ranging from 1.0 to 7.0, where a lower score is clinically worse than a higher score.
Once at baseline and 3 - 6 months later during follow-up
Change in frequency dependence of resistance (FDR) over the 3-6 months observation period compared to proposed minimal clinically important differences (MCIDs) (calculated for a one year interval) for FDR.
Time Frame: Once at baseline and 3 - 6 months later during follow-up
MCIDs over 1 year have been published for IOS parameters. For frequency dependence of resistance (FDR) the MCID is defined as a decline of FDR greater or equal to 0.06 kPa/(L.s). Change of FDR ≥ 0.06 kPa/(L.s) or not
Once at baseline and 3 - 6 months later during follow-up
Change in area of reactance (AX) over the 3-6 months observation period compared to proposed minimal clinically important differences (MCIDs) (calculated for a one year interval) for AX.
Time Frame: Once at baseline and 3 - 6 months later during follow-up
MCIDs over 1 year have been published for IOS parameters. For area of reactance (AX) the MCID is defined as a decline of AX greater or equal to 0.65 kPa/L. Change of AX ≥ 0.65 kPa/L or not
Once at baseline and 3 - 6 months later during follow-up

Collaborators and Investigators

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

Sponsor

Universitair Ziekenhuis Brussel

Collaborators

Vrije Universiteit Brussel

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 (Actual)

September 1, 2024

Primary Completion (Estimated)

April 1, 2026

Study Completion (Estimated)

April 1, 2026

Study Registration Dates

First Submitted

April 30, 2024

First Submitted That Met QC Criteria

May 17, 2024

First Posted (Actual)

May 22, 2024

Study Record Updates

Last Update Posted (Estimated)

September 15, 2025

Last Update Submitted That Met QC Criteria

September 8, 2025

Last Verified

September 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 24151_AM-IOS

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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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