Chronic COUGH Management in Interstitial Lung DisEase

Interstitial Lung Disease (ILD) comprises chronic, disabling, and progressive respiratory conditions marked by lung inflammation and fibrosis. The quality of life and functionality of people with ILD is affected by a plethora of debilitating symptoms such as dyspnoea, fatigue, and cough. Among them, chronic cough reigns as one of the most prevalent and challenging, despite receiving far less attention from researchers than other symptoms.

Chronic cough (a cough lasting for > 8 weeks) and affects up to 8 out of 10 individuals with ILD. It is associated with a worse prognosis, mortality, and the need for lung transplantation. This condition also causes urinary incontinence, interferes with speech, and presents psychosocial and physical manifestations, such as depression and chest pain. Chronic cough can also lead to relationship problems, such as couples sleeping in separate bedrooms, avoidance of public areas, reduced social interaction, and work absenteeism, further contributing to the decreased health-related quality of life experienced by this population. Managing chronic cough is, therefore, urgently needed.

Currently, there is no approved drug to manage chronic cough in people with ILD. Conversely, non-pharmacologic cough control therapies have demonstrated similar efficacy without side effects. Studies have shown that non-pharmacological cough control therapy can improve cough-related quality of life and reduce cough frequency in individuals with refractory (i.e., cough that lasts despite optimal treatment) chronic cough. Promising results were observed in a case-study on people with chronic cough and ILD. However, well-designed randomized controlled trials (RCTs) with adequate power are needed to establish the effects of non-pharmacological cough control therapy on people with ILD.

The primary aim of this study is to explore the effects of a non-pharmacological cough control treatment on cough-related quality of life in people with ILD. The specific aims of this study are: i) to explore short- and mid-term effects of the non-pharmacological cough control treatment on cough related outcomes (e.g., cough frequency and intensity, dyspnea, fatigue, cough self-efficacy, health-related quality of life and emotional status); ii) to identify (if any) adverse effects of this therapy.

COUGH-LESS randomized trial Potential participants will be identified and recruited through the pulmonology services of the Centro Hospitalar do Baixo Vouga (CHBV) and Centro Hospitalar de Entre-o-Douro e Vouga (CHEDV).

Study design Participants will be randomly assigned to an experimental (EG) or control group (CG) using an online software. Assessments will be conducted at baseline, post-intervention and 3 and 6 months after the intervention. To detect a 2-point between-group difference in the LCQ after 5 weeks, 20 participants per group (n=40) will be required, with 80% power and a significance level of 5%. Previous studies indicate losses to follow up of 50% and thus we will aim to recruit 60 individuals.

Data collection Assessments will be conducted at baseline, post-intervention and 3 and 6 months after the intervention.

Inclusion criteria

i) Adults (>18 years old) ii) Clinical diagnosis of ILD iii) Presenting chronic cough (> 8 weeks of duration) iv) People with access to a virtual meeting platform/telephone.

Exclusion criteria

i) Self-reports of moderate or large sputum production (> 2 tablespoons); ii) Actual or suspected exacerbation of the respiratory condition in the last month; iii) Upper respiratory tract infection (e.g. cold); iv) Use of angiotensin-converting enzyme inhibitor medication; v) Changes in prescribed medication in the last month; vi) Signs of cognitive impairment or significant cardiovascular, neurological and/or musculoskeletal disease that may limit participation in the program; vii) Inability to read or speak Portuguese; viii) Inability to provide informed consent.