Background: Idiopathic pulmonary fibrosis (IPF) is a severe interstitial lung disease with a dramatically poor prognosis and characterized by a radiological and histological pattern of usual interstitial pneumonia. Patients with IPF could develop acute exacerbation of IPF (AE-IPF) with an extremely bad prognosis. The objective of this study was to determine predicting and prognostic factors of AE-IPF.

Methods: We retrospectively analysed patients with IPF followed in Rennes University Hospital and in four local public hospitals. The incidence and outcomes of AE-IPF were investigated. Univariate and multivariate analyses were used to identify independent variables associated with AE-IPF.

Results: Within the 307 patients included, 81 (26.4%) patients developed AE-IPF in a median of 2.2 ± 2.0 years after diagnosis. Independently associated factors with AE-IPF were lower forced vital capacity (FVC) HR 0.94 [0.91; 0.97] (p = 0.0003), higher blood neutrophils and lymphocytes counts at diagnosis: respectively HR 1.01 [1.00; 1.01], (p = 0.0047), HR 1.13 [1.04; 1.22] (p = 0.0028). The median survival after AE-IPF was 5.39 months [2.6; 9.80]. AE-IPF was associated with a shorter median of survival: 2.84 years versus 4.33 years (p<0.0001).

Conclusion: The risk factors for AE-IPF identified in this cohort were a lower FVC and higher blood neutrophils and lymphocytes counts at diagnosis. More attention may be paid to the leukocytes counts at diagnosis. Further research is needed to confirm these results, ideally in prospective studies.