Bronchodilator Response in COPD and Asthma: Correlation Between Spirometry, IOS Indices, and Dyspnea Relief

Sponsor
Allergi- og Lungeklinikken, Elsinore
Study ID
NCT07364188
Status
Not Yet Recruiting

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Conditions

  • Asthma Bronchiale
  • Bronchodilation
  • COPD
  • Impedance
  • Small Airways Disease
  • Spirometry

Eligibility Criteria

Sex
ALL
Age
18 Years - N/A
Healthy Volunteers
Not accepted

Interventions

  • Bronchodilator — DIAGNOSTIC_TEST
    Classic beta-2-reversibility test

Study Details

A bronchodilator reversibility test is widely used in the diagnosis and management of obstructive lung diseases. Bronchodilators relieve symptoms in asthma and COPD. Traditionally, their effectiveness has been assessed using spirometric indices, particularly FEV₁. However, changes in FEV₁ often do not correlate well with patients' subjective experience of dyspnoea relief or with changes in small airway function. Impulse oscillometry (IOS) provides an effort-independent assessment of respiratory mechanics during tidal breathing and is more sensitive to small airway dysfunction than spirometry. Despite this, the clinical utility of IOS in routine COPD and asthma assessment remains underexplored, and its relationship to both spirometric response and symptom relief is not fully established, and the Minimal Clinically Important Difference (MCID) for IOS parameters has not been firmly established. Determining the MCID is essential for interpreting individual patient responses in a clinically meaningful way and for guiding treatment decisions in both research and practice. Hypothesis \& Aims In patients with either asthma or COPD baseline values and bronchodilator responses are compared. More specifically, this study aims to: 1. assess baseline correlations: Evaluate the correlation between ΔX5-baseline (EFL expiratory flow limitation=small airway collapse during expiration), RV/TLC-baseline, X5-average at baseline, FEV1-baseline, VAS-dyspnea at baseline, and ACQ-6-baseline. 2. compare bronchodilator responses across methods: Examine the correlation between bronchodilator-induced changes in FEV₁ and IOS parameters (including both average and delta values) and explore their relationship with short-term changes in dyspnea. 3. establish clinical relevance: Determine the MCID for key IOS variables using both anchor-based and distribution-based approaches, anchored to perceived changes in lung symptoms.

Key Dates

First listed
Jan 23, 2026
Start date
Feb 1, 2026
Status verified
Jan 2026
Primary completion
Dec 31, 2027
Completion
Dec 31, 2027

Study Design

Enrollment
120 participants (estimated)

Arms

  • Arm: Asthma
    FEV1/Forced Vital Capacity (FVC) \<0.7 at baseline (7) Visual Analog Scale (VAS) dyspnea score ≥10 (0-100, 100 max) (25,26). Doctor diagnosed asthma Less than 10 packyears. Exclusion Criteria: * Patients aged less than 18 years old. * Not able to perform spirometry or impulse oscillometry. * Cognitive disorders and not able to answer Asthma Control Questionnaire (ACQ), VAS dyspnea score, and COPD Assessment Test (CAT) score (25-28). * Short-acting beta-agonists 6 h, long-acting beta-agonists 2 days, short-acting anti-muscarinic agent 12 h, Long-acting anti-muscarinic agents 2 days. * Comorbidities with significant influence on dyspnea eg. bronchiectasis, ILS, mb. Cordis, lung resection, anemia, and active malignant disease * BMI ≥40 kg/m2.
  • Arm: COPD
    FEV1/Forced Vital Capacity (FVC) \<0.7 at baseline (7) Visual Analog Scale (VAS) dyspnea score ≥10 (0-100, 100 max) (25,26). Doctor diagnosed COPD Smokers or ex-smokers with ≥10 packyears Exclusion Criteria: * Patients aged less than 18 years old. * Not able to perform spirometry or impulse oscillometry. * Cognitive disorders and not able to answer Asthma Control Questionnaire (ACQ), VAS dyspnea score, and COPD Assessment Test (CAT) score (25-28). * Short-acting beta-agonists 6 h, long-acting beta-agonists 2 days, short-acting anti-muscarinic agent 12 h, Long-acting anti-muscarinic agents 2 days. * Comorbidities with significant influence on dyspnea eg. bronchiectasis, ILS, mb. Cordis, lung resection, anemia, and active malignant disease * BMI ≥40 kg/m2.

Primary Outcome Measure

FEV1 [ Time Frame: Before and 20 minuttes after inhaled Salbutamol 0.4 mg ]

Central Contacts

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