The Potential Added Value of Impulse Oscillometry in Asthma Monitoring

Not Applicable

Not yet recruiting

• Conditions: Asthma
• Interventions: Other: Full lung function; Other: Multiple breath nitrogen washout; Other: Impulse oscillometry

• Registration Number: NCT06425562
• Lead Sponsor: Universitair Ziekenhuis Brussel

Brief Summary

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.

Detailed Description

Not available

Study Timeline

• Status Verified: 2024-04
• Study First Submitted: 2024-04-30
• Study First Submitted QC: 2024-05-17
• Last Update Submitted: 2024-05-17
• Study First Posted: 2024-05-22
• Last Update Posted: 2024-05-22
• Study Start: 2024-09-01
• Primary Completion: 2025-09-01
• Study Completion: 2025-09-01

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 50

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

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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)

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Adult asthma patients	Full lung function	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.
Adult asthma patients	Multiple breath nitrogen washout	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.
Adult asthma patients	Impulse oscillometry	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.

Primary Outcome Measures

Name	Time	Method
Change in frequency dependance of resistance (FDR) stratified according to change in asthma control test (ACT)	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.
Change in area of reactance (AX) stratified according to change in asthma control test (ACT)	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.
Change in forced expiratory volume in 1 second (FEV1) stratified according to change in asthma control test (ACT)	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.

Secondary Outcome Measures

Name	Time	Method
Change in forced expiratory volume in 1 second (FEV1) stratified according to change in asthma control questionnaire (ACQ-6)	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.
Change in area of reactance (AX) stratified according to change in asthma quality of life questionnaire (AQLQ)	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.
Change in frequency dependence of resistance (FDR) stratified according to change in asthma control questionnaire (ACQ-6)	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.
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.	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
Change in area of reactance (AX) stratified according to change in asthma control questionnaire (ACQ-6)	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.
Change in frequency dependence of resistance (FDR) stratified according to change in asthma quality of life questionnaire (AQLQ)	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.
Change in forced expiratory volume in 1 second (FEV1) stratified according to change in asthma quality of life questionnaire (AQLQ)	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.
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.	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