Methacholine Challenge Testing: Comparison of FEV1 and IOS Parameters in Adult Asthma Patients

A classic methacholine challenge test is considered positive when forced expiratory volumen after one second (FEV1) decrease 20%. Impulse oscillometry (IOS) measures airway resistance and reactance, and seems more sensitive to changes in small airways. In adult asthma patients, we compare methacholine challenge test using both FEV1 and IOS.

Study Overview

• Status: Not yet recruiting
• Conditions: Bronchial Hyperreactivity
• Intervention / Treatment: Other: No intervention

Detailed Description

Asthma is a common chronic disease that is characterized by a history of variable respiratory symptoms and variable expiratory airflow limitation, and usually associated with airway hyperresponsiveness (GINA).

In general, FEV1 is used to test for airway hyperresponsiveness (AHR), and a 20% decrease after methacholine challenge is considered a positive test (Coates 2017; ERJ).

There is increasing recognition that the small airways are involved in 40-80% of patients with asthma, and the function of these airways is overlooked (the "silent zone") when measuring FEV1, which mainly reflects the function of the central airways (Cottini M, J Allergy Clin Immunol Pract 2019; Cottini M, 2022; Postma 2019 Lancet Respir Med).

Small airway dysfunction (SAD) can be assessed by IOS where pressure applied to the airways at a range of frequencies, and components of respiratory resistance and reactance are measured. Resistance at 5 Hz (R5) and 20 Hz (R20), respectively, represent total airway resistance and proximal airway resistance. The difference between these two values can be calculated (R5-R20). High R5-R20 and low reactance at 5 Hz (X5) indicate the presence of SAD.

A recent study showed that patients with a negative methacholine test measured by FEV1 may report asthma-like symptoms and may have a positive test when measured by IOS (Urbankowski; 2021). The question is whether these patients are a subgroup of patients with SAD (based on IOS at baseline) or are characterized in another way.

Knowledge on the proportion of patients with AHR only measured by IOS (not by FEV1) and the characteristics of these patients are sparse.

Hypothesis & Aims The aim of the present study was to determine the proportion of AHR to methacholine measured by FEV1 and IOS, respectively, in patients with diagnosed asthma and to compare patient characteristics and asthma medication in these four groups of patients: 1) negative by FEV1 and IOS; 2) negative by FEV1 but positive by IOS; 3) positive by FEV1 but negative by IOS; 4) positive by both tests.

• Study Type: Observational
• Enrollment (Estimated): 500

Contacts and Locations

• Study Contact: Name: Thomas Ringbæk, MSci; Phone Number: 004521969087; Email: thomasringbaek@gmail.com
• Study Contact Backup: Name: Lars Frølund, MSci; Phone Number: 004521777696; Email: lars.froelund@dadlnet.dk

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

This is a cross-sectional analysis of a single-centered, observational study on adult (≥18 years old) patients referred with known asthma or asthma-like symptoms to a lung specialist clinic

Description

Inclusion Criteria:

• Doctor diagnosed asthma (based on symptoms and at least one positive asthma test within the last 5 years (AHR; reversibility to beta2-agonist, ICS, prednisolone; peak flow variation).
• Written informed consent.

Exclusion Criteria:

• patients aged less than 18 years old.
• patients with an exacerbation or lower airway infection within 1 months.
• Pulmonary function test: FEV1 (% pred.) < 60%
• Not able to perform spirometry or body plethysmography.
• Cognitive disorders and not able to answer ACQ.
• Treated with biologics.
• Pregnancy or breastfeeding
• Short-acting beta-agonists 6 h, long-acting beta-agonists 2 days, short-acting anti-muscarinic agent 12 h, Long-acting anti-muscarinic agents 7 days, and Montelukast 3 days before methacholine challenge test (MCT).
• Comorbidity with significant influence on lung function and pulmonary symptoms eg. COPD, bronchiectasis, ischemic heart disease, heart failure, atrial fibrillation, uncontrolled hypertension (>160/100 mmHg), lung cancer, lung resection, BMI>40 kg/m2.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Asthma; Asthma according to Gina Guidelines	Other: No intervention; No intervention

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
ACQ-6	Asthma Control Questionnaire (ACQ6) will be used in the 6 sub-score version omitting FEV1 % of predicted	At entry (Cross sectional)
Biomarker	Serum eosinophils and hemoglobin will be measured	At entry
FeNO	Measurement of Exhaled Nitric Oxide by NOBreath	At entry
Impulse Oscillometry	Resistance at 5Hz (R5), R5-R20, reactance at 5Hz (X5), frequency response (Fres), areal under reactance curve (AX)	At entry
Demographic data	General demographic data, including age, sex (male/female), body mass index (BMI) (kg/m2), and smoking history will be recorded.	At entry
Lung function and body box	Forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and the percentage of FEV1 in the estimated value will be measured at baseline and after methacholine test by Vyntus, Vyaire Medical. Body plethysmography with residual volumen (RV), total lung capacity (TLC), diffusion capacity of the lungs for carbon monoxide (DLCO), will be measured before methacholine test by Medical Electronic Construction (MEC).	At entry
Asthma medication	Inhaled corticosteroids (ICS), long-acting beta2agonists (LABA), long-acting muscarinic antagonists (LAMA), Leukotriene antagonist, theophylline, and prednisolone - type and dose	At entry

Collaborators and Investigators

• Sponsor: Allergi- og Lungeklinikken, Elsinore
• Investigators: Principal Investigator: Thomas Ringbæk, MSci, Allergy and Lung Clinic Elsinore

Study record dates

Study Major Dates

• Study Start (Estimated): November 1, 2023
• Primary Completion (Estimated): November 1, 2024
• Study Completion (Estimated): November 1, 2024

Study Registration Dates

• First Submitted: September 5, 2023
• First Submitted That Met QC Criteria: September 5, 2023
• First Posted (Actual): September 13, 2023

Study Record Updates

• Last Update Posted (Actual): September 14, 2023
• Last Update Submitted That Met QC Criteria: September 12, 2023
• Last Verified: September 1, 2023

More Information

Terms related to this study

• Keywords: asthma; spirometry; oscillometry; bronchial hyperreactivity
• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Bronchial Diseases; Bronchial Hyperreactivity
• Other Study ID Numbers: Lungeklinikken_Elsinore

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: Publication in per-reviewed papers

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No