Plain English Summary
Background and study aims
Your nervous system allows your body to respond to changes in the environment by sending messages back and forth from the brain to different parts of your body. Your heart rate and blood pressure are controlled by your autonomic nervous system. Your heart rate and blood pressure change throughout the day, often in response to changes in your environment, such as standing up from a sitting position, or a change in temperature. In some people the autonomic nervous system does not always function correctly which can lead to problems such as light headiness or even fainting. Autonomic nervous system dysfunction has previously been studied in patients with other hypersensitivity disorders, such as asthma, but has not been previously studied in patients with chronic cough. This study aims to study autonomic function in people with chronic cough and healthy individuals to see whether there are any differences between the two groups.
Who can participate?
The study aims to recruit 20 chronic cough patients and 10 healthy volunteers with the same age distribution and proportion of males and females in each group.
What does the study involve?
This study involves three visits to the University Hospital of South Manchester. Visit 1 involves measuring and recording heart rate and blood pressure, an electrocardiogram (ECG), completion of three questionnaires designed to understand how coughing affects your daily life, a simple lung function test called spirometry, and fitting of a cough monitor, which is designed to record the number of times you have coughed during the day and how long for. This visit is anticipated to last about 1 hour. Visit 2 is a short visit and involves a cough challenge only, which is a test designed to make you to cough. This visit is anticipated to last about 30 minutes. Visit 3 is anticipated to last about 2 hours and 30 minutes and requires participants to fast for 4 hours prior to their appointment. Tests will be performed which are designed to affect blood pressure and heart rate, both of which will be monitored throughout the visit with respiratory bands, an ECG monitor and a beat-to-beat blood pressure monitor.
What are the possible benefits and risks of participating?
There will be no direct benefit for participants in this study. We hope that the results of this study will help us to understand the mechanisms of chronic cough. During the study you will be asked to perform a cough challenge which involves inhaling capsaicin, a component of chilli peppers. Capsaicin can cause tightening of the airways, although this is rare. Breathing tests are performed during and after the test to monitor any chest tightening, which is easily treated by inhaling salbutamol (a medication to open up the airways). A number of autonomic function tests will be performed during this study. These tests are designed to cause changes in your blood pressure and heart rate. As such these tests may make you feel light headed or even cause you to faint. If you do feel unwell you must tell a researcher. A doctor will be present during all autonomic function testing.
Where is the study run from?
This is a single centre study being conducted at the University Hospital of South Manchester. Healthy volunteers are being recruited from a list of volunteers stored in the North West Lung Research Centre at the University Hospital of South Manchester and chronic cough patients are being recruited from the tertiary referral cough clinic hosted by the University Hospital of South Manchester.
When is the study starting and how long is it expected to run for?
The study started recruiting in August 2013 and is expected to run until April 2014.
Who is funding the study?
University of Manchester, UK.
Who is the main contact?
Mrs Rachel Dockry, Research Assistant
Dr Jacky Smith
C/o University Hospital of South Manchester NHS Foundation Trust
North West Lung Research Centre
0161 291 5906
A study investigating autonomic dysfunction in chronic cough patients
Subjects with chronic cough will show evidence of sub-clinical autonomic dysfunction when compared to a healthy control group.
Note: The trial was initially submitted for ISRCTN registration on 21/08/2013. The ISRCTN registration was delayed due to miscommunication and finalised on 23/01/2014.
NRES Committee North West - Greater Manchester North, 04/03/2013, REC ref.: 13/NW/0148
Observational case-control single-centre study
Primary study design
Secondary study design
Patient information sheet
Not available in web format, please use the contact details below to request a patient information sheet.
This study involves a number of autonomic function tests which are designed to cause changes in your blood pressure and heart rate such as ECG monitoring, beat-to-beat blood pressure monitoring, Valsalva manoeuvre, deep metronomic breathing, voluntary coughing, capsaicin-induced cough, seated to standing test, cold pressor test and head up tilt test.
Primary outcome measures
The difference in heart rate variability in response to the Valsalva manoeuvre between the chronic cough group and the healthy control group.
Secondary outcome measures
1. To compare the heart rate variability response to autonomic function testing between chronic cough and healthy subjects
2. To compare the blood pressure response to autonomic function testing between chronic cough and healthy subjects
3. To compare the scores of the Survey of Autonomic Symptom between chronic cough and healthy subjects
We will be performing beat-to-beat blood pressure analysis on subjects whilst performing deep metronomic breathing, tilt table testing, cold pressor test, voluntary cough and capsaicin-induced cough. We will be comparing the blood pressure and heart rate responses between cases and controls. This is not a longitudinal study and therefore these measurements will be made on one occasion and not repeated at time points.
Overall trial start date
Overall trial end date
Participant inclusion criteria
1. Chronic cough subjects aged 18 and over or healthy volunteers aged 45 and over
2. Subject must be able to give informed consent
3. Normal spirometry
4. Cough subject only: chronic cough, defined as a cough lasting longer than 8 weeks despite investigation and/or treatment trials for cough variant asthma, post-nasal drip and gastro-oesophageal reflux disease
5. No significant respiratory diseases (except chronic cough in the patient group)
6. No known autonomic function disorders, neuropathy or neurological disorders
7. No history of syncope which is not related to cough
8. Current alcohol consumption exceeding government guidelines
Target number of participants
20 chronic cough subjects and 10 healthy age-matched control subjects with the same proportion of males and females in each group.
Participant exclusion criteria
1. Asthma, diabetes; cardiovascular disease, hypertension, irritable bowel syndrome (IBS), previous brain injury, history of myocardial infarction or any other disorder deemed unsuitable by the investigator
2. Current smoker or ex smoker (more than 10 pack years) and those still smoking within 6 months of the start of the study
3. Regular intense exercise, i.e. competitive sports
4. Blood pressure over 160/90 or abnormal ECG as determined by a medical doctor on screening
5. Pregnancy or breast-feeding
6. Use of angiotensin-converting-enzyme (ACE) inhibitors
7. Use of centrally acting medications that may affect the cough reflex (pregabalin and opiates may not be taken within 1 week of screening and throughout study)
8. History of drug or alcohol abuse
9. Current, treated depression
10. BMI greater than or equal to 32
11. Subjects taking anti-hypertensives; beta blockers; calcium channel blockers; anticholinergic medications or antidepressant treatment.
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
C/o University Hospital of South Manchester NHS Foundation Trust
The University of Manchester (UK)
Funding Body Type
Funding Body Subtype
Results and Publications
Publication and dissemination plan
Not provided at time of registration.
Intention to publish date
Participant level data
Not provided at time of registration
Results - basic reporting