Epidemiology and Survival of Systemic Sclerosis–Sarcoidosis Overlap Syndrome

Abstract

ObjectiveWe evaluated the epidemiology, manifestations, serology, comorbidities, and survival among patients with systemic sclerosis (SSc) with and without sarcoidosis.MethodsWe conducted a retrospective cohort study comparing patients with SSc with and without sarcoidosis. All patients fulfilled the American College of Rheumatology/European Alliance of Associations for Rheumatology classification criteria for SSc. Sarcoidosis was based on physician diagnosis and/or confirmatory biopsy. The primary outcome was time from diagnosis to all-cause mortality. Survival was evaluated using Kaplan-Meier curves.ResultsWe included 1977 patients (1971 with SSc, 6 with SSc–sarcoidosis) with a SSc–sarcoidosis prevalence of 0.30%. Sarcoidosis frequently preceded SSc (66.66%). The most frequent sarcoidosis manifestations were pulmonary (66.66%), lymphadenopathy (66.66%), arthritis (50%), cutaneous (33.33%), and hepatic (16.66%). Patients with SSc and SSc–sarcoidosis had female to male sex ratios of 4.5:1 vs 5:1 and median ages of SSc onset of 48.3 vs 43.8 years, respectively. Interstitial lung disease (35% vs 66.66%) and pulmonary hypertension (24.91% vs 50%) tended to occur more frequently whereas abnormal nailfold capillaries (34.7% vs 16.66%) and digital ulcers (33.33% vs 16.66%) tended to occur less frequently among patients with SSc–sarcoidosis, but the differences were not significant. There was an increased frequency of stroke among the patients with SSc–sarcoidosis (relative risk 8.59, 95% CI 1.02-72.00). The median survival times were 23.4 years for SSc–sarcoidosis and 18.6 years for SSc, with no differences in survival curves (log-rank test,P =0.55).ConclusionSarcoidosis in SSc is rare but appears to occur more frequently than in the general population. It is associated with pulmonary, lymph node, cutaneous, joint, and hepatic involvement. Stroke occurs more frequently in patients with SSc–sarcoidosis but with no differences in survival.