Systemic Sclerosis-associated Interstitial Lung Disease at 2 Tertiary Centers in the USA and Greece: A Comparative Study of Demographics, Management, and Radiologic Progression.

OBJECTIVE: To compare demographics, clinical features, treatment approaches, and outcomes of patients with systemic sclerosis-interstitial lung disease (SSc-ILD) at 2 geographically distinct tertiary centers: the University of Pennsylvania (UPenn), USA, and the University of Ioannina (UOI), Greece. METHODS: A cohort of 789 SSc patients (2013 ACR/EULAR criteria) was evaluated through medical records review at both institutions. Patients initially diagnosed with SSc-ILD between January 2020 and December 2024 with at least 72 weeks of follow-up were included. Sociodemographic, clinical, serological, and treatment data were systematically collected. ILD progression was defined as radiographic worsening on serial HRCT-comprising new or increased ground-glass opacification, reticulation, or traction bronchiectasis-as assessed at each center. PFTs were obtained at baseline and at 24, 48, and 72 weeks. RESULTS: Sixty-six patients were included (35 UPenn, 31 UOI). Arthritis (32.3% vs. 11.4%) and anti-Scl-70 positivity (64.5% vs. 40.0%) were more frequent at UOI. UOI patients had higher rates of rituximab (35.5% vs. 5.7%) and corticosteroid use (77.4% vs. 42.9%). ILD progression at 48 weeks was significantly greater in UPenn (57.1% vs. 17.2%, p<0.001). UOI patients reached specialist care faster (median 0.25 vs. 1.2 y from SSc diagnosis, p=0.001). On multivariate analysis, dcSSc, male sex, and study center were independent predictors of ILD progression. CONCLUSIONS: This study compares SSc-ILD presentation, management, and outcomes at 2 tertiary centers. UPenn showed a higher radiologic ILD progression rate, likely due to baseline disease severity, treatment differences, and referral timing. Nonetheless, these findings are observational; prospective, internationally standardized studies are needed to confirm these results.