Pleuroparenchymal fibroelastosis-like findings identify an idiopathic pulmonary fibrosis subgroup with shortened telomeres and poor prognosis.

Background: Idiopathic pulmonary fibrosis (IPF) is a progressive fibrosing interstitial lung disease (ILD) with poor prognosis. Radiological pleuroparenchymal fibroelastosis (PPFE)-like findings, characterised by upper-lobe subpleural fibrosis, have been associated with worse outcome in IPF. While short leukocyte telomere length (LTL) is a recognised prognostic factor, its relationship with PPFE-like findings remains unclear. Methods: We conducted a secondary analysis of an ongoing ILD cohort. IPF patients who underwent LTL measurement by quantitative PCR were classified into those with PPFE-like findings on high-resolution computed tomography (IPF/PPFE group) and those without such findings (IPF/usual interstitial pneumonia (UIP) group). Clinical characteristics, pulmonary function, telomere length and outcomes were compared. Age-adjusted LTL was evaluated using healthy controls. Prognostic factors were analysed using Cox regression. Results: Among 179 IPF patients, 29 (16%) were assigned to the IPF/PPFE group. Compared to the IPF/UIP group (n=150), the IPF/PPFE group had lower body mass index and forced vital capacity, and significantly shorter LTL (p=0.002), with more patients below the 10th percentile of healthy controls (37.9% Conclusions: IPF patients with PPFE-like findings constitute a distinct high-risk phenotype with shorter telomeres, accelerated progression, and poor prognosis. These findings highlight the clinical importance of recognising PPFE-like changes and telomere biology in IPF for risk stratification and emphasise the need for close monitoring and early intervention.