Understanding cough in interstitial lung disease: a cross-sectional study on the adequacy of treatment

Background: Cough is a common symptom in interstitial lung disease (ILD), often leading to treatment dissatisfaction for patients and physicians. Aim: To identify the prevalence and subjective adequacy of control of cough in patients with ILD. Methods: A cross-sectional study of patients with ILD attending a tertiary ILD clinic in Perth was undertaken using a pre-designed questionnaire that patients were invited to complete when attending clinic. Cough severity and impact on quality of life were assessed using a visual analogue scale and the validated Leicester cough questionnaire. Participants were asked to list triggers of their cough and strategies or medications trialled to control cough. Results: Of 164 respondents, 118 (72%) had cough, with prevalence common in all ILD subtypes. A lower forced vital capacity (FVC) was found in the cough group versus non-cough group (74.6 ± 18.7 vs 87.0 ± 15.9, P-value < 0.0001). Common reported triggers were lung irritants, exertion and doing routine daily activities. Avoidance of triggers was a common strategy to control cough. A high prevalence of non-ILD causes of cough was recorded in both groups. A variety of medications had been trialled, including anti-fibrotics, immunosuppression drugs, inhalers and proton pump inhibitors, with moderate benefit reported by 18% of participants. Conclusions: Cough is prevalent in ILD but is not adequately suppressed. Cough has a significant impact on quality of life, leading patients to adopt their own strategies to control their cough. More research is needed to understand cough mechanisms in ILD and the interplay of other potential co-pathologies.