Pleuroparenchymal fibroelastosis in patients with idiopathic pulmonary fibrosis

Background and objective PPFE is characterized by fibrosis in the pleura and subpleural lung parenchyma in the upper lobes, while other types of ILD, mainly UIP, can be observed in about half of the patients in their lower lobes. The aim of this study was to evaluate the clinical significance of the radiologically defined PPFE in patients with IPF. Methods Clinical data and chest CT images were retrospectively analysed in 445 patients with IPF (biopsy-proven cases, n = 165). The radiological criteria of PPFE were defined as follows: (i) bilateral subpleural dense fibrosis with or without pleural thickening in the upper lobes, (ii) evidence of disease progression and (iii) no clinical evidence of identifiable aetiologies. Results The median follow-up period was 43.0 months. The mean age of the patients was 66.4 years and 76.4% were male. PPFE was identified in 28 patients (6.3%). The PPFE group showed lower BMI and lung function (FVC and TLC) at baseline, more frequent pneumothorax and pneumomediastinum, higher decline rates in lung function and poorer prognosis during follow-up than the no-PPFE group. PPFE was an independent risk factor (HR = 2.953, 95% CI: 1.350-6.460, P = 0.007) for pneumothorax or pneumomediastinum, but not for mortality in patients with IPF. Conclusion Among patients with IPF, the PPFE group, when compared to the no-PPFE group, showed lower BMI and lung function and showed more frequent complications and poorer survival during follow-up.