Corticosteroid Responsiveness in Patients With Acute Exacerbation of Interstitial Lung Disease Admitted to the Emergency Department

Interstitial lung disease (ILD), particularly idiopathic pulmonary fibrosis (IPF), has a poor prognosis. Corticosteroids are widely used in the treatment of acute exacerbation of ILD (AE-ILD). This study aimed to clarify the causes of AE-ILD, determine the efficacy of corticosteroids for treating AE-ILD, and detect differences in the mortality rate among subgroups of ILD. This was an observational retrospective single-center study. Patients with ILD who presented to the emergency department with acute respiratory symptoms from January 1, 2016, to December 31, 2018, were included. Patients with AE-ILD were classified into two groups depending on the prednisolone dose: low dose (0 to 1.0 mg/kg) or high dose (>1.0 mg/kg). Mortality rates between patients with and without IPF were compared. This study included 182 patients with AE-ILD, including IPF (n=117) and non-IPF (n=65). Multivariate Cox regression analysis showed that corticosteroid dose (HR:0.221, CI:0.102–0.408, P <0.001), initial P/F ratio (HR:0.995, CI:0.992–0.999, P =0.006), and mechanical ventilation within 3 days of hospitalization (HR:4.205, CI:2.059–8.589, P 1 mg/kg prednisolone) in patients with AE-non-IPF-ILD. However, this was not the case in patients with AE-IPF.