Introduction:
Systemic sclerosis (SSc) is a rare autoimmune disease with possible life-threatening internal organ involvement. Because of its rarity and heterogeneous clinical presentation, studies on this disease may be difficult to carry out. We sought to describe patients at first hospitalization for SSc in Poland from 2013 to 2019. The study measured SSc incidence trend, comorbidities, and factors related to this disease among hospitalized patients in Poland.

Material and methods:
We conducted a retrospective, population-based study using hospital discharge records compiled by the National Institute of Public Health.

Results:
The study group consisted of 4,633 patients hospitalized with SSc diagnosis for the first time in 2013–2019. The mean and median age were 53.9 (95% CI: 53.4–54.3, SD = 16.6) and 57 years (IQR: 44–66). In the study group, female patients accounted for 81.3% of all patients, and they were significantly older than male patients (54.6 vs. 50.4 years; p < 0.001). The crude incidence was estimated at 1.72 per 100 000 person-years (95% CI: 1.67–1.77). The SSc incidence rate was significantly higher in urban than rural areas of Poland (1.83 vs. 1.46 per 100,000; p < 0.001). In patients with progressive systemic sclerosis in comparison to other forms of SSc we observed a significantly rare presence of selected groups of diseases.

Conclusions:
Presented data on SSc in Poland may also be helpful in comparative analyses in the European context. Territorial factors may have a significant impact on the occurrence of SSc in Poland.