Abstract

BACKGROUND: Familial idiopathic pulmonary fibrosis (f-IPF) is defined by the presence of at least two relatives with interstitial lung disease (ILD) in one family. We aimed to compare pulmonary function decline between sporadic IPF (s-IPF) patients and f-IPF patients.

METHODS: IPF patients referred to University Hospitals Leuven for multidisciplinary discussion (2016-2019), treated with antifibrotics and having =2 pulmonary function tests (PFTs) available were included. Patients were stratified according to a family history of a first-degree relative with ILD. PFTs (n=4757) were analyzed using linear mixed effect models.

RESULTS: Within the 439 included IPF patients, 63 f-IPF patients (14.4%) were identified. Annual decline in FVC%pred was -2.33 percentage point (pp) in s-IPF patients and -4.65 pp in f-IPF patients (p<0.01). Female gender (p<0.01) and negative smoking history (p<0.01) were significant predictors of FVC decline, while age (p=0.72), FVC%pred (p=0.07) and DLCO%pred (p=0.21) at diagnosis were not. In multivariate analysis including family history of ILD, gender, smoking history and FVC%pred, only a family history of ILD (p=0.01) and negative smoking history (p<0.01) remained significantly associated with FVC decline (fig.1).

CONCLUSION: Family history of a first-degree relative with ILD predicts FVC decline in IPF patients. A comprehensive family history assessment is important to inform patients about disease evolution.