PO:23:055 | Overlap of systemic sclerosis and Sjögren’s disease: insights from an Italian case-control study

Stefano Stano¹, Fabio Cacciapaglia^1|2, Maria Morrone¹, Simone Perniola¹, Marco Capodiferro¹, Marco Fornaro¹, Laura Coladonato¹, Giuseppe Lopalco¹, Florenzo Iannone¹. | ¹Rheumatology Unit - Department of Precision and Regenerative Medicine, Jonian Area DiPReMeJ, University of Bari, Bari, Italy; ²Rheumatology Service, Internal Medicine Unit F. Miulli General Hospital, Department of Medicine and Surgery, LUM Casamassima Italy.

Background. Patients with systemic sclerosis (SSc) may refer sicca symptoms, mainly due to glandular fibrosis but also in the setting of coexisting Sjögren’s disease (SjD)[1,2]. This overlap was first described in 1965[3], but available data on the characteristics of patients with concurrent SSc and SjD remain limited and outdated.

Materials and Methods. This case-control study aimed to characterize a large cohort of Italian patients with overlapping SSc and SjD (SSc/SjD), and to identify significant clinical and immunological differences compared to patients with isolated SSc or SjD. METHODS Patients included in the SSc/SjD cohort fulfilled both the 2013 ACR/EULAR classification criteria for SSc[4] and the 2016 ACR/EULAR criteria for SjD[5]. The control groups (1:2 ratio) consisted of patients with a diagnosis of SSc or SjD only, without further rheumatological overlap, consecutively seen between January and December 2024. The clinical data of the studied groups were extracted from the medical records and analysed with appropriate statistical tests using GraphPad Prism v9.

Results. A total of 50 patients with SSc/SjD (98% women, mean age ± SD: 67±11 years) were included, compared to 100 patients with SSc alone and 100 patients with SjD alone. Patients with SSc/SjD were significantly older than those with isolated SSc (p<0.01) or SjD (p<0.001) and had a longer disease duration than patients with SSc (p<0.001). In terms of autoimmunity, SSc/SjD patients presented more frequently positive ANA (p<0.01), anti-CENP (p<0.0001), and anti-TopoI (p<0.0001) antibodies than those with SjD alone. Anti-SSA antibodies were more common in SSc/SjD than in SSc (p<0.0001), whereas anti-SSB antibodies were less common in SSc/SjD than in SjD (p<0.0001). Clinical features of the SSc/SjD group are detailed in Table. Sicca symptoms were more prevalent in SSc/SjD compared to SSc (p<0.0001). Interstitial lung disease (ILD) was more frequent in SSc/SjD than in SjD (p<0.0001), and comparable to SSc alone. However, SSc/SjD patients showed lower predicted diffusing capacity for carbon monoxide (DLCO) than both SSc (p=0.02) and SjD (p<0.01) groups. Cutaneous subsets and modified Rodnan skin scores (mRSS) were similar between SSc/SjD and SSc. The occurrence of telangiectasias, Raynaud’s phenomenon, digital ulcers, and osteolysis was comparable between SSc/SjD and SSc, although pitting scars were more frequent in SSc/SjD (p=0.01). The prevalence of pulmonary hypertension, gastrointestinal involvement, and calcinosis was also similar between SSc/SjD and SSc. Corticosteroid use was more common in SSc/SjD compared to SSc (p=0.04), whereas biologic agents use was less frequent in SSc/SjD than in SjD (p<0.05). Finally, fibromyalgia was less common (p<0.0001), and neoplasia occurred more frequently (p=0.02) in SSc/SjD than in SjD.

Conclusions. Presence of neoplastic diseases and ILD with low DLCO characterize the SSc/SjD overlap. Therefore, active screening is recommended, as this may affect outcomes and indicate the need for a personalized approach.