Incidence and changes in treatment of acute exacerbation of idiopathic pulmonary fibrosis in Japan: A claims-based retrospective study

Acute exacerbation is an essential prognostic factor in idiopathic pulmonary fibrosis (IPF) and is the leading cause of death in Japanese patients with IPF. Its epidemiology, treatment status, and effect on IPF progression have been insufficiently investigated. We examined the incidence of acute exacerbation and treatment status before and after the onset of acute exacerbation in Japanese patients with IPF to provide basic information for treatment strategies.A Japanese claims database (April 2008-March 2019) from acute-care hospitals was analyzed. Incidence of acute exacerbation, time to the next event, and percentages of patients who received each treatment by the year before and after the onset of acute exacerbation were examined in patients diagnosed with IPF at least once. Acute exacerbation was defined according to the use of steroid pulse therapy.We identified 9961 patients with IPF and 2629 acute exacerbations (average age at the time of acute exacerbation: 74.8 years, percentage of men: 79%). The annual incidence of acute exacerbation was approximately 10% between 2010 and 2018. The time to the next acute exacerbation shortened with increasing number of these events. The percentage of patients receiving antifibrotic drugs remained constant (30%-40%) throughout the period. The percentages of patients receiving steroid therapy, immunosuppressive drugs, and oxygen therapy increased after the onset of acute exacerbation compared with before the onset.The annual incidence of acute exacerbation was approximately 10% in recent years. It is suggested that acute exacerbation worsens respiratory function in patients with IPF.