Cough Suppressive Therapy in Patients With Chronic Cough

Overview

In this randomized, placebo-controlled, interventional study on chronic cough a non-pharmacological cough suppressive therapy is the intervention to be studied, with a control group receiving treatment consisting of general healthy lifestyle advice. The following data will be collected before, after and up to six months after treatment: Standardized questionnaires for diagnosis of background factors, Leicester Cough Questionnaire (LCQ), Work Ability Index (WAI), and cough frequency as well as lung function and biomarkers. The primary treatment effect measurement will be changes in chronic cough-related quality of life, measured by the Leicester Cough Questionnaire (LCQ).

The study will be carried out in collaboration between respiratory physicians, clinical physiologists, physiotherapists, speech- and language therapists and gastroenterologists. The primary hypothesis of the planned study is: The cough suppressive therapy improves chronic cough-related quality of life and work ability, and is sustained over six months after treatment. The secondary hypotheses of the planned study are: Treatment of chronic cough by the cough suppressive therapy can reduce cough frequency (measured by an automated cough detector), airway inflammation and airway resistance. Baseline differences in clinical findings, biomarkers and physiologic measurements predict different treatment effects. The following data will be collected before and after treatment: * Standardized questionnaires for diagnosis of background factors and cough duration, LCQ, WAI, questions on sick leave days, voice disturbance questionnaire. * Physiological measurements: Spirometry with reversibility test, impulse oscillometry before and after provocation with hypertonic saline inhalation. 24 hours cough frequency analysis, voice analysis. * Biomarkers: Fractional exhaled nitric oxide (FeNO), blood-eosinophils and eosinophil cationic protein in serum, proteomics in particles in exhaled air (PExA)