Pleuroparenchymal fibroelastosis in systemic sclerosis: prevalence and prognostic impact

Interstitial lung disease (ILD) in systemic sclerosis (SSc) is a major cause of morbidity and mortality. Little is known about the prevalence of pleuroparenchymal fibroelastosis (PPFE),a specific entity affecting the visceral pleura and subpleural parenchyma. The main aims of this study were to estimate the prevalence of PPFE in two large cohorts of SSc patients and to assess its impact on survival and functional decline. A total of 359 SSc patients,derived from two referral centers in two different countries (UK and Italy), were included. The first available high-resolution computed tomography scan was independently evaluated by two radiologists to quantify ILD extent, lobar percentage involvement of PPFE and freestanding bronchial abnormalities.Discordant scores were adjudicated by a third scorer.PPFE extent was further classified as limited or extensive. Results were evaluated against functional decline and mortality.Cox proportional hazard analysis was used to investigate determinants of mortality. The overall prevalence of PPFE in the combined SSc population was 18%(11% with extensive PPFE), with no substantial difference between the two cohorts. PPFE was independently linked to worse survival on a multivariable analysis,including age, ILD severity, short term functional decline, pulmonary hypertension, and body mass index (HR 2.07,95% CI 1.15-3.72;p<0.001).A significant association with free-standing bronchial abnormalities was also found (p<0.0001). The present study provides a thorough assessment of PPFE prevalence, associations and clinical impact in the largest cohort of SSc subjects published to date. PPFE presence should be carefully considered, due to its prognostic implications.