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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
Cough suppression therapy as a treatment for patients with cough following a respiratory illness
Scientific title
Cough suppression therapy as a treatment for acute persistent cough following an upper respiratory tract infection
Secondary ID [1] 301317 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Common cold 317504 0
Infectious respiratory disease 317926 0
Condition category
Condition code
Respiratory 315603 315603 0 0
Other respiratory disorders / diseases
Infection 315963 315963 0 0
Other infectious diseases

Study type
Description of intervention(s) / exposure
The cough suppression therapy involves advice regarding vocal hygiene particularly increasing hydration and reducing exposure to laryngeal irritants, avoid deliberate coughing and throat clearing using cough suppression strategies, reduce oral breathing to prevent irritation of the laryngeal mucosa, and reduce laryngeal strain if present. Patients will be given handouts of (1) vocal hygiene advice, and (2) the cough suppression exercises. Handouts will be developed for this study.
Therapy will be delivered by a qualified speech pathologist delivered in a single 1 hour session.
The mode of delivery will be face to face at the Hunter Medical Research Institute, Newcastle, Australia, but telehealth appointments will be considered for patients who are unable to travel to the appointment.Intervention adherence will be measured at each follow up session and include estimation of whether the patient has implemented the strategies, demonstration of the strategies and implementation of the strategies to interrupt cough episodes. Intervention fidelity will be assessed after every participant for the first five participants and then if satisfactory, after every 10 participants.
Intervention code [1] 317613 0
Treatment: Other
Comparator / control treatment
The control intervention will be a single session of healthy lifestyle education delivered by a qualified speech pathologist. The education will include:
• Education on the causes of common cold
• Cough etiquette
• Education regarding strategies to reduce risk of spreading virus
• The role of viruses in the development of cough
• The typical course and duration of upper respiratory tract infection
• Advice regarding diet, exercise and stress management.
This treatment will last approximately 1 hour.
Control group

Primary outcome [1] 323839 0
Number of patients with significant cough. Significant cough is defined as cough severity of 40mm or more on a 100mm visual analogue scale.
Timepoint [1] 323839 0
26 weeks after randomisation
Secondary outcome [1] 383033 0
Between group differences in change in cough quality of life measured with the Leicester Cough Questionnaire
Timepoint [1] 383033 0
Baseline, 8, 12 and 26 weeks post onset of cough
Secondary outcome [2] 383930 0
Between group differences in cough severity visual analogue scale scores
Timepoint [2] 383930 0
Baseline, 8, 12 and 26 weeks post onset of cough
Secondary outcome [3] 383931 0
Between group differences in change in Vocal Cord Dysfunction Questionnaire scores
Timepoint [3] 383931 0
Baseline and 8, 12 and 26 weeks post onset of cough
Secondary outcome [4] 384801 0
Laryngeal hypersensitivity questionnaire scores
Timepoint [4] 384801 0
Baseline and 8, 12 and 26 weeks post onset

Key inclusion criteria
• 18 years of age or older.
• Cough between 3 and 6 weeks duration following upper respiratory tract infection
• Cough severity visual analogue scale>39mm
• Non-productive cough
• Probable viral infection as defined by the Common Cold Questionnaire
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
1. Primary diagnosis of history of cough secondary to lower airway disease
2. Haemoptysis
3. Productive cough of > 1 table spoon phlegm per day.
4. Cystic fibrosis
5. Bronchiectasis/bronchitis
6. Chronic obstructive pulmonary disease
7. Interstitial lung disease
8. Cognitive impairment, poor English language skills or significant untreated hearing impairment that prevents completion of data collection forms or understanding verbal instructions.
9. Inability to attend study visits.
10. Current smoker or smoker with >20 pack-year smoking history
11. Prominent dyspnoea, especially at rest or at night
12. History of unexplained weight loss
13. Chest pain
14. Current pneumonia
15. Medical concern regarding diagnosis

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Randomisation will be done via computer. The person confirming the participant eligibility will be blind to the allocation.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using a randomisation table created by computer software
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s

The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
A previous study of acute cough found that chronic cough persisted following upper respiratory tract infection in 29/188 (15.4%) patients. To reduce the incidence of chronic cough by 50% (i.e. only 7.5% of participants develop chronic cough), 84 participants would be needed (42 in each arm). Allowing for a 20% attrition rate this brings the required sample size to 101.

The primary outcome will be the proportion of participants in each group who have chronic cough at 6 month follow up which will be analysed using a Chi Square test of proportions.

Secondary outcomes two are between group differences of change in questionnaire scores from baseline to six months (Leicester Cough Questionnaire, cough severity VAS, Laryngeal Hypersensitivity Questionnaire, and Vocal Cord Dysfunction Questionnaire. Secondary outcomes will be assessed using a two way Anova to compare change from pre- and post-treatment assessments and between groups. Data will be analysed by intention to treat.

Recruitment status
Not yet recruiting
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment hospital [1] 16699 0
John Hunter Hospital - New Lambton
Recruitment postcode(s) [1] 30298 0
2305 - New Lambton

Funding & Sponsors
Funding source category [1] 305753 0
Name [1] 305753 0
John Hunter Hospital
Address [1] 305753 0
Locked Bag 1
Hunter Region Mail Centre
NSW 2310
Country [1] 305753 0
Primary sponsor type
John Hunter Hospital
Locked Bag 1
Hunter Region Mail Centre
NSW 2310
Secondary sponsor category [1] 306188 0
Name [1] 306188 0
Address [1] 306188 0
Country [1] 306188 0

Ethics approval
Ethics application status
Ethics committee name [1] 306027 0
Hunter New England Human Research Ethics Committee
Ethics committee address [1] 306027 0
Hunter New England Research Office
Level 3
Hunter Medical Research Institute
Lot 1
Kookaburra Circuit
New Lambton Hts
NSW 2305

Ethics committee country [1] 306027 0
Date submitted for ethics approval [1] 306027 0
Approval date [1] 306027 0
Ethics approval number [1] 306027 0

Brief summary
Cough commonly occurs after upper respiratory tract infection. The aim of the study is to determine whether early intervention for acute cough following upper respiratory tract infection (common cold) reduces the proportion of patients who develop chronic cough.

The study involves a randomised control trial of intervention for acute cough involving 101 participants. Participants will undergo a baseline assessment and brief intervention. Follow-up visits to determine whether cough has persisted, reduced resolved will occur at 8, 12 and 26 weeks post-onset of cough.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 102470 0
A/Prof Anne Vertigan
Address 102470 0
Speech Pathology
John Hunter Hospital
Locked Bag 1
Hunter Region Mail Centre
NSW 2310
Country 102470 0
Phone 102470 0
+61 2 49213726
Fax 102470 0
Email 102470 0
Contact person for public queries
Name 102471 0
A/Prof Anne Vertigan
Address 102471 0
Speech Pathology
John Hunter Hospital
Locked Bag 1
Hunter Region Mail Centre
NSW 2310
Country 102471 0
Phone 102471 0
+61 2 49213726
Fax 102471 0
Email 102471 0
Contact person for scientific queries
Name 102472 0
A/Prof Anne Vertigan
Address 102472 0
Speech Pathology
John Hunter Hospital
Locked Bag 1
Hunter Region Mail Centre
NSW 2310
Country 102472 0
Phone 102472 0
+61 2 49213726
Fax 102472 0
Email 102472 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
What supporting documents are/will be available?
No other documents available
Summary results
No Results