Abstract
Background: Although the third most frequent interstitial lung disease, hypersensitivity pneumonitis (HP) remains an enigmatic disease without clear diagnostic and therapeutic guidelines. We assessed the effect of the commonly used therapeutic interventions (i.e. exposure avoidance and corticosteroid treatment) in an HP cohort. Methods: We collected clinical data of all HP patients followed at our centre between January 1, 2005, and December 31, 2016. HP patients were stratified according to the presence of fibrosis on chest CT. Survival was analysed using the multivariate Cox proportional hazards model. Forced vital capacity (percent predicted, FVC%) and diffusing capacity of the lung for carbon monoxide (percent predicted, DLCO%) evolution were analysed using linear mixed-effect models. Results: Two hundred and two HP patients were identified: 93 non-fibrotic HP (nfHP) and 109 fibrotic HP (fHP), experiencing a monthly FVC% decline before treatment of 0.93% and 0.56%, respectively. While nfHP had an excellent survival, fHP patients experienced a median survival of 9.2 years. Corticosteroid treatment and exposure avoidance did not result in survival differences. Although nfHP patients showed FVC% and DLCO% increase after corticosteroid initiation, no therapeutic effect was seen in fHP patients. FVC% and DLCO% increased in nfHP patients after exposure avoidance, while a positive numerical trend was seen for FVC% after exposure avoidance in fHP patients (p = 0.15). Conclusions: nfHP patients experienced an excellent survival with good therapeutic effect on pulmonary function tests with both corticosteroid initiation as well as antigen avoidance. In contrast, fHP patients experienced a dismal prognosis (median survival of 9.2 years) without any therapeutic effect of corticosteroid treatment. Whether antigen avoidance is useful in fHP patients is still unclear.
Highlights
Hypersensitivity pneumonitis (HP) is the third most frequent interstitial lung disease (ILD) [1], characterized by an aberrant immunological reaction upon a antigen, which can lead to a profibrotic response [2,3]
Overview of cohort formation is presented in Supplementary Figure S1. fibrotic HP (fHP) patients were older, multidisciplinary discussion
As the classical classification of hypersensitivity pneumonitis (HP) patients into acute HP (AHP) and chronic HP (CHP) is based on symptoms types and symptoms chronicity, we investigated whether these factors would influence survival and pulmonary function tests (PFT) evolution in the non-fibrotic HP (nfHP) patients of the cohort
Summary
Hypersensitivity pneumonitis (HP) is the third most frequent interstitial lung disease (ILD) [1], characterized by an aberrant immunological reaction upon a (mainly organic) antigen, which can lead to a profibrotic response [2,3]. Therapeutic approach consists mainly of antigen avoidance and. Stratification of HP patients is classically based on symptom chronicity as well as presenting symptoms [8,9,10]. Recent literature suggested stratification based on radiologic and histopathologic features, would correlate more with the natural history of the disease [11,12]: HP patients with fibrosis have a prognosis of only 5–8 years—far worse compared to HP patients without fibrosis [13,14,15,16,17,18]. We sought to investigate the therapeutic effect on survival and pulmonary function test evolution of both antigen avoidance and corticosteroid initiation in both non-fibrotic HP (nfHP). Fibrotic HP (fHP) with the hypothesis that treatment effects would be different between these two subgroups
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