Prognostic Value of Lung Ultrasound B-Lines in Systemic Sclerosis

Background: A high percentage of systemic sclerosis (SSc) patients experience interstitial lung disease (ILD) during the disease course. Recent data have shown that lung ultrasound (LUS) can assess ILD by the evaluation of B-lines, the sonographic sign of pulmonary interstitial involvement. Research Question: To establish the prognostic value of B-lines in a large number of patients with SSc. Study Design and Methods: A total of 396 consecutive patients with SSc, who were enrolled at three Rheumatology Departments, underwent a comprehensive LUS examination on the anterolateral and posterior chest for a total of 58 scanning sites. All available clinical, imaging, and functional data were recorded. Patients were followed after enrolment to establish the prognostic role of LUS. Results: The median number of B-lines was higher in patients with the diffuse cutaneous subset (44 vs 17 B-lines; P < .0001), topoisomerase I autoantibodies (39 vs 16 B-lines; P < .0001), and the presence of ILD at chest high-resolution CT (45 vs 9 B-lines; P < .0001). At multivariable analysis, the number of posterior B-lines ≥5 was associated with new development or worsening ILD (hazard ratio, 3.378; 95% CI, 1.137-9.994; P = .028), with additional value over topoisomerase I positivity. The prognostic value was further confirmed in the subgroup of patients with known ILD at baseline (hazard ratio, 1.010; 95% CI, 1.003-1.018; P = .008). Interpretation: Lung ultrasound B-lines are associated with worsening or development of pulmonary deterioration. In the near future, LUS might become part of the diagnostic and prognostic armamentarium in patients with SSc, which would allow a more sustainable and user-friendly approach to this very fragile population.