Inducible Laryngeal Obstruction in Severe Asthma in Severe Asthma

Study Overview
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Brief Summary
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The first part will be a comparative cross-sectional study to identify the frequency of ILO and other comorbidites among participants with asthma compared to a group of reference subjects without asthma, matched for age- and gender and race. The second part will be a longitudinally observational study study following participants for one year after the cross-sectional study. The Maat-scores ILO-symptoms and asthma-outcomes longitudinally will be evaluated, .

Detailed Description
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Inducible laryngeal obstruction (ILO) is characterized by inappropriate closure of the structures of the larynx causing reduced airflow. The symptoms are breathing difficulties that resemble those seen in asthmatic patients, such as dyspnea, coughing and stridor. ILO may be diagnosed by the continuous laryngoscopy during exercise test (CLE-test), where the larynx is visualized live on video as the patient runs to exhaustion on a treadmill whilst having a laryngoscope placed through the nose. The prevalence of ILO in asthmatic patients will be assesed by preforming a CLE-test twice in all participants at baseline and again after one year. Participant will be given visual feedback and instructed in breathing techniques. Others common comorbidities will be assessed by questionnaires and clinical interview. All patients with asthma will have a respiratory polygraph recording. Changes in ILO-symptoms and asthma-symptoms and outcomes will be assessed after 1 year.

Official Title
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Inducible Laryngeal Obstruction in Severe Asthma

Conditions
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Asthma Chronic, Vocal Cord Dysfunction

Intervention / Treatment
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* Diagnostic Test: Continous laryngoscopy exercise test
* Diagnostic Test: Overnight respiratory polygraphy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with severe asthma (GINA 5) Patients with mild-moderate well-treated asthma (GINA step 1-4) Agroup of age- and gender matched control subjects without asthma also aged 18- 70. The patients must have had a stable disease the last one month before performing the CLE-test Exclusion Criteria: No have underlying neurologic disease. No known cancer in the lung-head-neck No known vocal cord pathology. No history of life-threatening asthma required hospitalization.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Severe asthma<br>Gina-guidlines treatment-step 5 | Diagnostic Test: Continous laryngoscopy exercise test<br>* Participants walks on a tredmill with a a flexible naso-laryngoscope in the larynx allowing visulasion of the larynx and obstructions in the larynx at the epiglottic og glottic levels are scored<br>Diagnostic Test: Overnight respiratory polygraphy<br>* Overnight respiratory polygraphy is a continuous recording of nasal airflow, thoracic and abdominal movements, heart rate and oxygen saturation during the night used to detected sleep apnoea<br>|
| Mild-moderate asthma<br>Gina-guidlines treatment-step 1-4 | Diagnostic Test: Continous laryngoscopy exercise test<br>* Participants walks on a tredmill with a a flexible naso-laryngoscope in the larynx allowing visulasion of the larynx and obstructions in the larynx at the epiglottic og glottic levels are scored<br>Diagnostic Test: Overnight respiratory polygraphy<br>* Overnight respiratory polygraphy is a continuous recording of nasal airflow, thoracic and abdominal movements, heart rate and oxygen saturation during the night used to detected sleep apnoea<br>|
| Subjects without asthma<br>Matches control-group without asthma | Diagnostic Test: Continous laryngoscopy exercise test<br>* Participants walks on a tredmill with a a flexible naso-laryngoscope in the larynx allowing visulasion of the larynx and obstructions in the larynx at the epiglottic og glottic levels are scored<br>Diagnostic Test: Overnight respiratory polygraphy<br>* Overnight respiratory polygraphy is a continuous recording of nasal airflow, thoracic and abdominal movements, heart rate and oxygen saturation during the night used to detected sleep apnoea<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Prevalence of ILO in the participants | Continues during exercise(CLE)-test score at 2 or more at glottis or supraglottic level (Score range 0 minimum -3 maximum) 3 is full closure, 0 i open. | One year | 
| Changes in continues during exercise (CLE-)-test score | The absolute change from baseline CLE-score (Score range 0 minimum -3 maximum). 3 is full closure in larynx, 0 is open. | One year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The prevalence of OSA in asthma patients with ILO. | Prevalence of mild ( apnea-hypopnea index (AHI )5-15 ) moderat (AHI 15-30) and severe (AHI > 30 )OSA in participents with asthma and ILO | One year | 
| Changes in asthma-controll score (ACT) | Changes of 3 points of ACT-score are considered a clinical relevant change, score (score range minimum 5, maximum 25) | One year | 
| Number of asthma-exercabations | Annual asthma exacerbation rate and the precentage of patients with at least one asthma exacerbation. Asthma exacerbations are defined as worsening of asthma symptoms, and in participants on stable regimen with oral glucocorticoids, a doubling of the dose for 3 or more days or the use of systemic glucocorticoids for at least 3 days or beeing hospitalized. | One year | 
| Changes in mini-Asthma quality of life (m-AQLQ) | Changes of 0.5 at m-AQLQ are considered a clinical relevant change | One year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Inducible laryngeal dysfunction, Severe asthma,