The incidence of interstitial lung disease in patients with systemic sclerosis: rate, risk factors and prognostic implications in a EUSTAR cohort analysis (CP 133).

Abstract

Interstitial lung disease (ILD) carries significant morbidity and mortality risk in systemic sclerosis (SSc). We aimed to estimate the incidence of new-onset SSc-ILD and the associated risk factors, as well as its impact on the prognosis. Patients classified as having SSc, with the absence of ILD signs on high-resolution computed tomography (HRCT) at baseline and having at least 1 follow-up visit with available HRCT data, were selected. SSc-ILD incidence was calculated as a rate per 100 person-years. Predictors of new-onset ILD and risk factors for ILD progression and mortality were chosen according to the literature and expert opinion. Risk factors for new-onset ILD, as well as its prognostic impact on ILD progression and mortality, were tested by generalised logistic estimating equation and Cox regression models, respectively. Among 5331 patients with SSc with negative baseline HRCT, the incidence of new-onset ILD was 3.83 cases per 100 person-years. Notably, there was a continuous detection of new ILD onset up to 10 years from baseline. Risk factors for new-onset ILD included New York Heart Association stage ≥2, muscle weakness, high inflammatory markers, and SSc-specific autoantibodies, but not disease duration. Despite a lower risk of ILD progression compared with prevalent ILD diagnosed at baseline, incident ILD still carried an increased risk for mortality, which was almost double when compared with ILD-negative cases. Patients with SSc should be considered for regular screening following a negative baseline HRCT, in particular when carrying high-risk features for new ILD onset, given its incidence and prognostic implications.