Calcinosis is associated with digital ulcers and osteoporosis in patients with Systemic Sclerosis: A Scleroderma Clinical Trials Consortium Study

Objectives We sought to identify the clinical factors associated with calcinosis in an international multicenter collaborative effort with the Scleroderma Clinical Trials Consortium (SCTC). Methods This is a retrospective cohort study of 5218 patients with systemic sclerosis (SSc). Logistic regression was used to obtain odds ratios (OR) relating calcinosis to various clinical features in multivariate analyses. Results A total of 1290 patients (24.7%) had calcinosis. In univariate analyses, patients with calcinosis were older than patients without calcinosis, more likely to be female, and had longer disease duration from the first non-Raynaud phenomenon symptom. Patients with calcinosis were more likely to have digital ulcers, telangiectasias, acro-osteolysis, cardiac disease, pulmonary hypertension, gastrointestinal involvement, arthritis, and osteoporosis, but less likely to have muscle disease. Anti-Scl-70, RNA-polymerase-III, and U1-RNP autoantibodies were significantly less common in patients with calcinosis, while anticentromere (ACA), anti-PM/Scl, and anticardiolipin antibodies were more frequent. In multivariate analysis, the strongest associations with calcinosis were digital ulcers (OR = 3.9; 95% CI: 2.7–5.5; p < 0.0001) and osteoporosis (OR = 4.2; 95% CI: 2.3–7.9; p < 0.0001). Conclusion One quarter of patients with SSc have calcinosis at some time during their illness. Our data confirm a strong association of calcinosis with digital ulcers, and support a novel association with osteoporosis.