Characteristics and association with survival of respiratory-related hospitalization in Japanese idiopathic pulmonary fibrosis patients

Background: The characteristics and significance of respiratory-related hospitalization in patients with idiopathic pulmonary fibrosis (IPF) in Asian countries remain unknown. The purpose of this study was to define the characteristics of respiratory-related hospitalization and to inspect the relationship between respiratory-related hospitalization and subsequent survival in patients with IPF in Japanese general practice. Methods: Patients with IPF who underwent clinical evaluation between February 2008 and August 2017 were screened. Only those who had undergone evaluation within 1 year after the diagnosis of IPF were included in the study. The post-diagnosis pulmonary function tests were considered the registration point. We then performed a 6-month landmark analysis including only patients who were alive 6 months after the registration. The characteristics of respiratory-related hospitalizations during the 6 months after registration and the association between respiratory-related hospitalization and survival were investigated. Results: A total of 106 patients with IPF were included in the study. The mean forced vital capacity (FVC) at registration was 80.2 +/- 25.1% predicted. Seventeen patients (16.0%) had respiratory-related hospitalization during the 6 months after registration. Pneumonia was the most frequent reason for hospitalization (47.0%), followed by acute exacerbation of IPF (29.4%). In multivariate analysis, % predicted FVC (hazard ratio: 0.98, 95% confidence interval: 0.96-0.99, p = 0.004), 6-month decrease in % predicted FVC (1.05, 1.02-1.08, 0.005), and respiratory-related hospitalization (2.45, 1.24-4.85, 0.009) were significantly associated with survival. Conclusions: Pneumonia is the most frequent cause of respiratory-related hospitalization in Japanese IPF patients. Furthermore, respiratory-related hospitalization is significantly associated with subsequent poor survival. (C) 2019 Published by Elsevier B.V. on behalf of The Japanese Respiratory Society.