Impact of the revised definition on incidence and outcomes of acute exacerbation of idiopathic pulmonary fibrosis

Abstract

The revised definition of acute exacerbation (AE) in idiopathic pulmonary fibrosis (IPF) was proposed in 2016, but changes in the incidence and impact on prognosis of the re-defined AE compared to those of the previous definition remain unclear. Clinical data of 445 patients with IPF (biopsy proven cases: 165) were retrospectively reviewed. The median follow-up period was 36.8 months and 17.5% (n = 78) experienced AE more than once. The 1- and 3-year incidence rates of AE were 6.7% and 16.6%, respectively, and idiopathic AE accounted for 82.1% of AE. Older age, lower diffusing capacity of the lung for carbon monoxide and 10% relative decline in forced vital capacity for 6 months were independently associated with AE. The in-hospital mortality rate following AE was 29.5%. In the multivariable analysis, AE was independently associated with poor prognosis in patients with IPF. Compared to the old definition, the revised definition relatively increased the incidence of AE by 20.4% and decreased the in-hospital mortality by 10.1%. Our results suggest that the revised definition affects approximately 20% increase in the incidences and 10% reduction in the in-hospital mortality of AE defined by the past definition.

Figure 1

Comparison of incidence of AE of IPF according to 2007 and 2016 definition of AE. AE acute exacerbation, IPF idiopathic pulmonary fibrosis.

Figure 2

(A) Comparison of survival curves from diagnosis of IPF between AE, no-AE RD and no-RD groups among patients with IPF. (B) Comparison of survival curves after hospitalization in patients with AE according to 2007 and 2016 definition of AE. AE acute exacerbation, RD respiratory deterioration, IPF idiopathic pulmonary fibrosis.

Figure 3

Change in the incidence of AE in patients with IPF according to 2007 and 2016 definition of AE. IPF idiopathic pulmonary fibrosis, AE acute exacerbation, RD respiratory deterioration.