Systemic sclerosis in Israel clinical characteristics, ethnic and spatial disparities: A nationwide study.

BACKGROUND: Systemic sclerosis (SSc) is an autoimmune disease characterized by immune dysregulation, vasculopathy and fibrosis. Epidemiology, Geographical and ethnic variation of SSc in Israel has not been reported. OBJECTIVES: To estimate SSc prevalence, incidence and mortality in Israel, and to identify ethnic and geographic patterns in disease distribution. METHODS: We conducted a nationwide epidemiologic and ecological study of SSc across Israeli localities using Clalit Health Services data. Prevalent cases and population denominators were analysed. Spatial autocorrelation was assessed using Moran's I and Local Indicators of Spatial Association (LISA). Associations between ethnicity and SSc prevalence were examined using negative binomial regression and Bayesian spatial Poisson models, adjusting for socioeconomic status (SES). RESULTS: The study included 3567,009 individuals from 1205 localities and 2866 SSc patients. Prevalence increased from 107 per million in 2000 to 627 per million in 2023, while incidence remained stable (≈2.8-3. 9 per 100,000/year). The standardized mortality rate was 2.88. SSc prevalence showed significant spatial autocorrelation (Moran's I = 0.065, p < 0.001), with clusters in northern Israel. In non-spatial models, Druze localities had higher prevalence than Jewish localities (PRR 1.45, 95% CI 1.04-2.01), while Arab localities did not differ. After spatial adjustment, Arab localities showed lower prevalence (RR 0.78, 95% CI 0.64-0.94). Druze localities showed the highest prevalence . Higher SES was associated with increased prevalence. CONCLUSIONS: SSc prevalence in Israel is among the highest reported worldwide and shows marked spatial clustering. Ethnic differences vary after accounting for spatial dependence, with consistently high prevalence in Druze localities.