The Belgian Systemic Sclerosis Cohort: correlations between disease severity scores, cutaneous subsets, and autoantibody profile.

Objective: To report baseline and followup data on the first 438 patients with systemic sclerosis (SSc) included in the Belgian Systemic Sclerosis Cohort.

Methods: According to LeRoy and Medsger's classification, 73 patients with limited SSc (lSSc), 279 with limited cutaneous SSc (lcSSc), and 86 with diffuse cutaneous SSc (dcSSc) were included. History was collected and clinical examination, blood tests, and paraclinical investigations were repeated. The Disease Activity Score (DAS) and Disease Severity Score (DSS) of several organ systems were computed. An organ system was considered to demonstrate SSc if the corresponding DSS was ≥ 1.

Results: At baseline, patients with dcSSc had more general, joint/tendon, muscle, gastrointestinal, and kidney involvement. Mean DLCO was below normal in patients with lSSc, indicating unsuspected lung involvement. Patients with anti-Scl-70 had more vascular, skin, joint/tendon, and lung involvement. Patients with anti-RNA polymerase III had more skin and joint/tendon involvement compared to patients with anticentromere. Time to death was statistically shorter for patients with dcSSc. New-onset lung disease was the most common complication over time. No changes in DAS were observed. By contrast, the general and the skin DSS worsened in patients with lcSSc and lSSc, respectively. Fifteen percent of patients with lSSc shifted to lcSSc at Month 30, but neither serology nor capillaroscopy findings at baseline were helpful in identifying those at risk.

Conclusion: Our data indicate that the DSS can be used to define organ involvement in SSc. Differences can be seen between subsets classified not only according to cutaneous subtypes but also to autoantibody profile.