Global, regional, and national incidence and prevalence of systemic sclerosis

To estimate the global and country-specific unbiased epidemiological data of SSc. Epidemiological studies were systematically searched in four databases. A Bayesian hierarchical linear mixed model was constructed to estimate epidemiological data. 82 studies were included and epidemiological data on SSc were missing for 83.9% of countries worldwide. The global SSc incidence and newly diagnosed population were estimated to be 8.64 per 100,000 person-years (1.78–23.57) and 0.67 million (0.14–1.84) people annually, respectively. Regarding prevalence, the global SSc prevalence and affected population were 18.87 per 100,000 persons (1.55–25.28) and 1.47 million (0.12–1.97) people, respectively. Relatively higher incidence and prevalence were observed in females, adults, and high-income level countries. We provide a comprehensive synthesis of SSc epidemiology and fill data gaps in most countries. Especially in low- and middle-income countries, epidemiological studies of SSc are insufficient. Further large-scale and standardized reported epidemiological investigations of SSc are imperative.