Incidence of acute exacerbation of idiopathic pulmonary fibrosis in patients receiving antifibrotic agents: Real-world experience.

BACKGROUND: Acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF) is a fatal event that can occur during the clinical course of idiopathic pulmonary fibrosis (IPF). Although data from clinical trials suggest that the antifibrotic agents pirfenidone and nintedanib might reduce the risk of AE-IPF, the incidence of AE-IPF in patients receiving antifibrotic agents in clinical settings is unclear. OBJECTIVES: To determine the incidence of AE-IPF in patients receiving antifibrotic agents and compare AE-IPF frequency in patients receiving pirfenidone and nintedanib. METHODS: We retrospectively reviewed the clinical records of 199 patients with IPF who were started on pirfenidone or nintedanib at our institution during the period from 2009 through 2018. Baseline characteristics, incidence of AE-IPF, and outcome after AE-IPF onset were analyzed. RESULTS: During the observation period, the 1-, 2-, and 3-year cumulative incidences of AE-IPF were 9.3 %, 22.1 %, and 25.0 %, respectively. The 1-, 2-, and 3-year cumulative incidence rates for AE-IPF in the pirfenidone group and nintedanib group were 5.1 % vs. 18.6 %, 20.4 % vs. 25.2 %, and 22.6 % vs. 29.6 %, respectively. AE-IPF incidence was significantly lower in patients treated with pirfenidone than in those treated with nintedanib (log rank test, P = 0.035). The 3-month survival rate after AE-IPF onset was 61.1 % in the pirfenidone group and 61.5 % in the nintedanib group; thus, outcomes after AE-IPF onset were similar in the 2 groups. CONCLUSION: The reduction in AE-IPF risk might be greater for pirfenidone than for nintedanib.