Clinical features of idiopathic pleuroparenchymal fibroelastosis with progressive phenotype showing a decline in forced vital capacity

BackgroundIdiopathic pleuroparenchymal fibroelastosis (IPPFE) is heterogeneous, with some patients showing a progressive decline in forced vital capacity (FVC). However, the clinical features of these cases with progressive phenotypes remain unknown.MethodsThis retrospective study included 48 patients diagnosed with IPPFE who underwent longitudinal pulmonary function tests at our institution from 2005 to 2021. The progressive phenotype was defined as a relative decline of ≥10% in %FVC within two years from diagnosis of IPPFE, and its clinical features were evaluated.ResultsOf the 48 patients, 23 (47.9%) were classified as progressive IPPFE. They were significantly older with a higher rate of dyspnea, fine crackles on chest auscultation, lower-lobe usual interstitial pneumonia (UIP) pattern on high-resolution computed tomography, and lower %FVC at diagnosis than non-progressive IPPFE. Additionally, progressive IPPFE had a significantly higher rate of long-term oxygen therapy requirement, the incidence of pneumothorax, and weight loss after diagnosis, which showed worse survival than non-progressive IPPFE. The relative decline in %FVC and weight loss showed a significant positive correlation. Multivariate analysis revealed that lower body mass index tended to predict early progression, and the coexistence of lower-lobe UIP pattern was significantly associated with early progression. A decline in %FVC was an independent poor prognostic factor in IPPFE.ConclusionsWith a progressive decline in %FVC, IPPFE often has an advanced stage at diagnosis and lower-lobe UIP pattern and is associated with weight loss and worse survival.