The Efficacy of Corticosteroid Therapy in Fibrotic Hypersensitivity Pneumonitis: A Propensity Score-matched Cohort Analysis

Abstract Background: Fibrotic hypersensitivity pneumonitis (HP) is a chronic interstitial lung disease caused by allergic responses to repeated exposures to a causative antigen. Therapeutic evidence of corticosteroid for fibrotic HP remains lacking, although corticosteroid is recognized as a major treatment option. The purpose of this study was to evaluate the efficacy of corticosteroid for patients with fibrotic HP in a propensity score-matched cohort. Methods: Retrospective medical record review from 2005 to 2019 in a single center was conducted to identify 144 patients with fibrotic HP. Semiquantitative scores of lung abnormalities on HRCT were evaluated. Patients with corticosteroid treatment (PDN group) and without the treatment (non-PDN group) were matched using a propensity score method. Survival rates and serial changes in pulmonary function, and annual changes in HRCT scores werecompared between pair-matched patients. Results: In the matched analysis, 30 of the PDN group were matched with 30 of the non-PDN group, the majority of which comprised ILD without extensive fibrosis. The survival rate was significantly better in the PDN group (P = 0.032for the stratified Cox proportional hazards model; HR, 0.250). Absolute changes in %FVC at 6, 12, and 24 months from baseline were significantly better in the PDN group. Fewer cases experienced annual deterioration in HRCT scores in the non-PDN group for ground-glass attenuation, consolidation, reticulation, traction bronchiectasis and honeycombing. Conclusions: Fibrotic HP without extensive fibrosis may receive benefits from corticosteroid treatment in terms of improvements in survival rate and pulmonary function decline and inhibition of fibrotic progression. We propose that early initiation of corticosteroid be considered for fibrotic HP when worsening fibrosis is observed.