tetano
Editor, Senior Moderator
Respir Investig
. 2025 Nov 17;64(1):101326.
doi: 10.1016/j.resinv.2025.11.005. Online ahead of print. Impact of the COVID-19 pandemic on acute exacerbation of idiopathic pulmonary fibrosis: a nationwide observational study in Japan
Yuichi Ohteru[SUP] 1 [/SUP], Tomoyuki Kakugawa[SUP] 2 [/SUP], Masahiro Kakugawa[SUP] 3 [/SUP], Tsunahiko Hirano[SUP] 4 [/SUP], Kazuto Matsunaga[SUP] 4 [/SUP]
Affiliations
Background: The coronavirus disease 2019 (COVID-19) pandemic and associated infection control measures drastically reduced respiratory infections worldwide. This unique context facilitated a natural investigation of the role of respiratory infections in triggering acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF). The aim of this study was to evaluate changes in AE-IPF incidence, seasonality, and prognosis before and during the pandemic using a nationwide Japanese database.
Methods: This retrospective cohort study was based on hospitalization data from April 1, 2018 to March 31, 2022. Pandemic-related changes in AE-IPF incidence, seasonal trends, and outcomes were assessed with respect to the pre-pandemic period using mixed-design analysis of variance and Kaplan-Meier survival analysis. For comparison, similar changes in chronic obstructive pulmonary disease (COPD) exacerbation were examined using the same methods.
Results: Despite reduced respiratory infections, AE-IPF incidence did not decrease during the pandemic. While the typical winter surge in respiratory infections disappeared during the pandemic, the seasonal increase in AE-IPF incidence during winter persisted. However, the incidence of COPD exacerbations decreased significantly, and the seasonality of exacerbations shifted during the pandemic.
Conclusions: The findings of this study question the prior assumption that respiratory infections are key contributors to AE-IPF. While respiratory infections may play a role in some cases, our results suggest that, at least for pre-pandemic respiratory infections, their overall contribution may be less substantial than that previously assumed. This underscores the need to reconsider the pathogenesis of AE-IPF and explore noninfectious mechanisms with regard to its management.
Keywords: Acute exacerbation; Coronavirus disease 2019; Idiopathic pulmonary fibrosis; Pandemic; Respiratory infection.
. 2025 Nov 17;64(1):101326.
doi: 10.1016/j.resinv.2025.11.005. Online ahead of print. Impact of the COVID-19 pandemic on acute exacerbation of idiopathic pulmonary fibrosis: a nationwide observational study in Japan
Yuichi Ohteru[SUP] 1 [/SUP], Tomoyuki Kakugawa[SUP] 2 [/SUP], Masahiro Kakugawa[SUP] 3 [/SUP], Tsunahiko Hirano[SUP] 4 [/SUP], Kazuto Matsunaga[SUP] 4 [/SUP]
Affiliations
- PMID: 41253080
- DOI: 10.1016/j.resinv.2025.11.005
Background: The coronavirus disease 2019 (COVID-19) pandemic and associated infection control measures drastically reduced respiratory infections worldwide. This unique context facilitated a natural investigation of the role of respiratory infections in triggering acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF). The aim of this study was to evaluate changes in AE-IPF incidence, seasonality, and prognosis before and during the pandemic using a nationwide Japanese database.
Methods: This retrospective cohort study was based on hospitalization data from April 1, 2018 to March 31, 2022. Pandemic-related changes in AE-IPF incidence, seasonal trends, and outcomes were assessed with respect to the pre-pandemic period using mixed-design analysis of variance and Kaplan-Meier survival analysis. For comparison, similar changes in chronic obstructive pulmonary disease (COPD) exacerbation were examined using the same methods.
Results: Despite reduced respiratory infections, AE-IPF incidence did not decrease during the pandemic. While the typical winter surge in respiratory infections disappeared during the pandemic, the seasonal increase in AE-IPF incidence during winter persisted. However, the incidence of COPD exacerbations decreased significantly, and the seasonality of exacerbations shifted during the pandemic.
Conclusions: The findings of this study question the prior assumption that respiratory infections are key contributors to AE-IPF. While respiratory infections may play a role in some cases, our results suggest that, at least for pre-pandemic respiratory infections, their overall contribution may be less substantial than that previously assumed. This underscores the need to reconsider the pathogenesis of AE-IPF and explore noninfectious mechanisms with regard to its management.
Keywords: Acute exacerbation; Coronavirus disease 2019; Idiopathic pulmonary fibrosis; Pandemic; Respiratory infection.