C104-10 Cough Burden in Hypersensitivity Pneumonitis and its Response to Treatment

Rationale Hypersensitivity pneumonitis (HP) is an immune-mediated interstitial lung disease (ILD) that is driven by repeated inhalational exposure to environmental antigens in susceptible individuals. Cough is a prominent and often distressing symptom in HP that contributes significantly to morbidity and impaired quality of life. This, however, remains poorly characterised, especially in relation to objective measures, underlying clinical determinants and response to therapeutic interventions. A clearer understanding of cough behaviour in HP would better inform patient-centred approaches to disease monitoring and clinical management. Methods To address this knowledge gap, a prospective cohort of patients with fibrotic HP diagnosed per ATS/JRS/ALAT guidelines criteria were recruited. Baseline assessments included the cough visual analogue (VAS) and the Leicester cough Questionnaire (LCQ) to quantify symptom severity and impact. Objective Cough frequency was recorded using the VitaloJAK cough monitor in a subset of patients. Multivariable models were used to identify independent clinical predictors of cough severity. In incident, treatment-naïve cases, changes in both subjective and objective cough reported measures were evaluated at three months following the initiation of corticosteroid therapy. Results A total of 101 patients were recruited. The median cough VAS was 35 mm (IQR 14-50mm) and the median LCQ was 15.2 (IQR 13.2-17.4). Among the subset of objective recordings (n = 28), the median cough count was 8.7/hr (range 0.2-32.1/hr).Subjective cough scores showed strong correlation with objective cough frequency (cough VAS ρ = 0.693, P = <0.001 and LCQ ρ = - 0.555, P = 0.002). Female sex, reduced forced vital capacity (FVC) and higher bronchoalveolar (BAL) lymphocyte fractions emerged as independent predictors of cough severity. Corticosteroids significantly improved subjective cough (cough VAS -13.7mm, P = 0.002 and LCQ +1.9 P < 0.001 (n = 44)) but had no significant effect on objective cough frequency (n = 16). Lung function remained unchanged at three months post treatment. Conclusions These findings demonstrate that corticosteroid therapy can meaningfully improve patient-reported cough symptoms in HP, even in the absence of measurable reductions in objective cough frequency. This dissociation between subjective and objective cough outcomes highlights the complex and multifactorial nature of cough in HP, potentially reflecting neurogenic or inflammatory mechanisms beyond those directly captured by physiological measurements. This study underscores the need for integrated assessment strategies and further research into targeted antitussive therapies, to better address cough in this patient population. This abstract is funded by: The work was supported by the National Institute for Health & Care Research through the Imperial Biomedical Research Centre, the Manchester Biomedical Research Centre and the Clinical Research Facility at Guy’s and St Thomas’ NHS Foundation Trust. PLM is supported by the Asthma+Lung UK Chair award.