Systemic sclerosis overlap and non-overlap syndromes share clinical characteristics but differ in prognosis and...

To screen for concomitant autoimmune disease in patients with systemic sclerosis (overlap SSc) and to describe their clinical characteristics and prognosis.

This was a two-center retrospective observational study. Patients diagnosed with SSc according to the 2013 ACR-EULAR scleroderma classification criteria were screened for concomitant rheumatoid arthritis (RA), Sjögren syndrome (SgS) and systemic lupus erythematosus (SLE). Patient characteristics were retrieved from the medical records and were compared to those of a non-overlap SSc cohort.

Among the 534 SSc patients studied, thirty-four (6.4%) were identified as having overlap SSc. There were 21 (3.9%) patients with RA, 14 (2.6%) with SgS and 4 (0.7%) with SLE (5 patients had 2 AISD) . The disease phenotype of overlap SSc was similar to that of non-overlap SSc in terms of cutaneous phenotype, prevalence of pulmonary arterial hypertension, interstitial lung disease, digital ulcers and mortality. Using a multivariate Cox model, age (HR = 1.04, 95% CI [1.02-1.07]), the modified Rodnan skin score (HR = 1.08 per point, 95% CI [1.05-1.11]), and the presence of concomitant SgS (HR = 3.79, 95% CI [1.38-10.40]) were significantly associated with mortality. Overlap SSc were more likely to receive corticosteroids (85.3% vs. 45%, p < 0.001), immunosuppressive drugs (82.4% vs. 49.2%, p < 0.001) and biologics (52.9% vs. 3.8%, p < ZZ0.001).

While overlap and non-overlap SSc shared common characteristics, patients with SgS/SSc had a higher risk of mortality, and those with RA/SSc received more corticosteroids, methotrexate and biologics. Screening for an associated AISD should be promoted since their co-occurrence with SSc may affect prognosis and treatments.