The Usefulness of the Methacholine Challenge Test and Capsaicin Inhalation Cough Challenge in a Prediction of Response to Management in Adults With a Chronic Cough.
Trial Snapshot
- Phase
- Not Applicable
- Status
- Completed
- Sponsor
- Enrollment
- 55
- Locations
- 1
- Primary Endpoint
- The decrease of a cough after cough variant asthma therapy measured by Visual Analogue Scale (VAS).
Study Overview
Brief Summary
The aim of the study is to assess the prevalence of bronchial hyperresponsiveness (BHR) in non-smoking adults with chronic cough and the prevalence of BHR in patients with upper airway cough syndrome (UACS) and gastroesophageal reflux disease (GERD), to evaluate the relationship between BHR and cough reflex sensitivity, to assess the diagnostic accuracy of methacholine challenge test (MCT) in cough variant asthma (CVA) with special regard to its discriminating cut off value between CVA and other causes of chronic cough, particularly GERD, to estimate prognostic value of BHR, fractional exhaled nitric oxide (FeNO) and induced sputum eosinophil count in predicting response to asthma treatment.
Patients diagnosed with a chronic cough will undergo the standard diagnostic work-up recommended by experts for patients with a chronic cough, including methacholine challenge test (MCT) and an at least 4-week period of causal treatment. Patients with BHR in MCT will be treated with - in first step B2-agonist and inhaled corticosteroid (ICS) for at least 4 weeks, if improvement is not significant in next steps with leukotriene receptor antagonist (LTRA) or systemic corticosteroid. A good treatment response, evaluated by visual analogue scale (VAS), Leicester Cough Questionnaire (LCQ) and cough challenge will confirm the diagnosis of the disease. A statistical analysis will consist of the frequency of BHR in a chronic cough, correlation between the results of MCT and cough reflex sensitivity in capsaicin inhalation test and cut-off point for MCT to discriminate asthma from other causes of a chronic cough.
Detailed Description
The present study has the following objectives:
- to assess the prevalence of BHR in non-smoking adults with a chronic cough,
- to assess the prevalence of BHR in patients with UACS and GERD,
- to evaluate the relationship between BHR and cough reflex sensitivity,
- to assess the diagnostic accuracy of MCT in CVA with special regard to its discriminating value between CVA and other causes of a chronic cough, particularly GERD,
- to estimate prognostic value of BHR, fractional exhaled nitric oxide (FeNO) and induced sputum eosinophil count in predicting response to asthma treatment.
The investigated group will consist of 80 non-smoking adults (18-75 years old), who are not treated with angiotensin-converting enzyme inhibitors, with no signs of respiratory infection within six weeks prior to enrolment, with a normal chest radiograph and who are referred to the hospital due to a cough lasting at least eight weeks.
After obtaining an informed consent, the diagnostic approach of the most common causes of chronic cough will be performed: a medical history, physical examination, chest radiograph, in some cases chest computed tomography, pulmonary function tests (spirometry, fractional exhaled nitric oxide, methacholine challenge test), laboratory tests (total immunoglobulin E concentration, complete blood count), skin prick tests, induced sputum cell count, computed tomography of the paranasal sinuses and ENT consultation, 24-hour impedance with pH monitoring, videolaryngoscopy and cough challenge with capsaicin.
The cough severity will be assessed twice (on admission and after six weeks of causal treatment) using the Visual Analogue Scale (VAS), the Polish version of the Leicester Cough Questionnaire (LCQ) and the capsaicin inhalation cough challenge.
Study Design
- Study Type
- Observational
- Observational Model
- Cohort
- Time Perspective
- Prospective
Eligibility Criteria
- Ages
- 18 Years to 75 Years (Adult, Older Adult)
- Sex
- All
- Accepts Healthy Volunteers
- No
Inclusion Criteria
- •Adults patients aged between 18 and 75;
- •Chronic cough lasting more than 8 weeks;
- •Non-smoking (min. 6 months);
- •Not treated with angiotensin-converting enzyme (ACE) inhibitors;
- •Not treated with:
- •inhaled corticosteroids or systemic corticosteroids min. 4 weeks before enrolment,
- •proton pump inhibitors min. 2 weeks before enrolment,
- •antihistaminic drugs 1 week before enrolment;
- •With normal chest radiograph or with insignificant changes in cough pathogenesis
- •Without airway infection in previous 6 weeks.
- •Patients enrolled with informed consent.
Exclusion Criteria
- •Patients under 18 years old and above 75 years old;
- •Smokers (actual or ex-smokers shorter than 6 weeks);
- •Therapy with corticosteroids (inhaled or systemic) for last 4 weeks, proton pump inhibitors for 2 weeks, antihistaminic drug for 1 week before enrolment;
- •Airway infection 6 weeks preceding enrolment or during study - re-attempt to enroll after 6 weeks
Outcomes
Primary Outcomes
The decrease of a cough after cough variant asthma therapy measured by Visual Analogue Scale (VAS).
Time Frame: at least 4 weeks of treatment
Reduction of cough intensity measured by VAS: Reduction min. 20 mm in VAS
The decrease of a cough after cough variant asthma therapy measured by the cough challenge.
Time Frame: at least 4 weeks of treatment
Increase capsaicin concentration causing causing two/five (C2/C5) cough episode in the cough challenge.
The decrease of a cough after cough variant asthma therapy measured by Leicester Cough Questionnaire (LCQ).
Time Frame: at least 4 weeks of treatment
Increase in quality of life measured with LCQ min. 1.3 points.
Secondary Outcomes
No secondary outcomes reported