A multicentre, prospective registry of patients with systemic sclerosis in Japan: baseline patient characteristics

Objectives: We established a multicentre prospective registry of patients with systemic sclerosis (SSc) in Japan to evaluate the outcomes in the modern treatment era. This report presents the baseline characteristics of patients enrolled in the registry. Methods: Adult SSc patients were prospectively enrolled from 20 medical centres across Japan. Baseline data, including demographics, organ involvement, autoantibody profiles, and patient-reported outcomes, were collected using a dedicated electronic data capture system. Results: A total of 835 patients were eligible for analysis. The cohort was predominantly female (85.1%), with a median age of 64 years at enrolment, and 35.0% had diffuse cutaneous SSc. Autoantibodies included anticentromere (38.9%), anti-topoisomerase I (topo I; 33.5%), anti-RNA polymerase III (RNAP III; 12.4%), and anti-U1 RNP (12.9%). Interstitial lung disease (ILD) was the most common organ manifestation (56.0%), followed by upper gastrointestinal (GI) involvement (42.5%), heart involvement (5.3%), pulmonary hypertension (3.4%), scleroderma renal crisis (1.9%), and lower GI involvement (1.2%). Patients with anti-topo I had the worst patient global assessment, whereas those with anti-RNAP III patients had the worst physician global assessment. Conclusions: This prospective registry captures real-world data on SSc patients, providing a valuable resource for understanding the clinical spectrum and outcomes in contemporary practice in Japan.