An investigation of cough responses to a variety of inhaled irritants in order to compare the mechanisms underlying cough in health and disease

Not Applicable

• Conditions: Asthma, chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF) or chronic cough; Respiratory; 1. Asthma2. Chronic obstructive pulmonary disease (COPD)3. Idiopathic pulmonary fibrosis (IPF)4. Chronic cough

• Registration Number: ISRCTN34161400
• Lead Sponsor: niversity Hospital of South Manchester

Brief Summary

Not available

Detailed Description

Not available

Study Timeline

• Study Start: 2016-01-08
• Last Update Posted: 24 June 2024
• Study Completion: 2025-01-07

Recruitment & Eligibility

• Status: Ongoing
• Sex: All
• Target Recruitment: 100

Inclusion Criteria

All participants:
1. Aged 18 years and over

Healthy volunteers:
1. Normal spirometry
2. No current or past history of chronic cough or respiratory disease
3. Non-smokers or ex-smokers (>6months abstinence) with smoking history of = 10 pack years

Asthma:
1. Physician diagnosis of asthma
2. Evidence of airways hyper-responsiveness to methacholine (PC20<16mg/ml) or significant bronchodilator reversibility (>12% FEV1) within the last 2 years.
3. Non-smokers or ex-smoker (>6months abstinence) with a smoking history of = 20 pack years
4. The subjects treated with:
4.1. Short acting Beta 2 Agonist PRN
4.2. AND/OR inhaled corticosteroid (=250mcg fluticasone propionate daily or equivalent)

COPD
1. Physician diagnosis of COPD
2. Ex-smokers (> 6 months abstinence) with smoking history of = 20 pack years
3. Spirometry demonstrating airflow obstruction i.e. FEV1/FVC ratio <70%

Idiopathic Pulmonary Fibrosis
1. Diagnosis of idiopathic pulmonary fibrosis following review by a Multi-Disciplinary Team (MDT).
2. Non-smokers or ex-smoker (>6months abstinence) with a smoking history of =20 pack years
Refractory Chronic Cough
3. History of a dry/minimally productive cough for 12 months
4. Normal spirometry
5. No clinically significant findings to explain chronic cough on CXR or CT scan of thorax
6. Completed appropriate investigation and/or trials of treatment for common causes of chronic cough
7. Non-smokers or ex-smoker (>6months abstinence) with a smoking history of =20 pack years

Exclusion Criteria

All participants:
1. Ex-smokers with <6 months abstinence
2. Upper respiratory tract infection within last 4 weeks
3. Exacerbation of respiratory disease in the last 4 weeks requiring additional medication.
4. A change in regular medication within the past 4 weeks prior to screening
5. Patients with severe respiratory disease e.g. FEV1 <1 litre, requirement of oxygen therapy
6. Use of ACE inhibitors
7. Use of centrally acting medications that may alter the cough reflex e.g. opiates, gabapentin, pregabalin, amitriptyline (unless they are willing and medically able to withdraw from such medication for the duration of the study and sought advice from their GP or clinician)
8. History of drug or alcohol abuse
9. Pregnancy or breastfeeding
10. Concomitant conditions which may alter cough responses e.g. diabetes mellitus with autonomic neuropathy, Parkinson’s disease, stroke.
11. Concomitant conditions which affect the subjects’ ability to participate in the study.
12. Uncontrolled hypertension (i.e., >165/95 mmHg despite adequate medical therapy).
13. Allergy or intolerance of salbutamol

Asthma:
1. Subjects treated with high dose inhaled corticosteroid (>250mcg fluticasone propionate daily or equivalent)

Idiopathic Pulmonary Fibrosis
1. High dose systemic steroids i.e. prednisolone >20mg daily or equivalent. Those patients on lower doses of steroids for >1 month may be included
2. Resting blood oxygen saturation of <90 %
3. Concurrent use of pirfenidone, unless receiving a stable dose for at least 4 weeks prior to screening
4. A history of concomitant asthma or obstructive airway disease, or those with an FEV1/FVC ratio at screening of <70%

Study & Design

• Study Type: Interventional
• Study Design: Not specified