Causes of severe infections in patients with systemic sclerosis and associated factors

Systemic sclerosis (SSc) is a chronic systemic disease characterized by vascular damage, autoimmunity, and fibrosis in the skin and internal organs. In this study, we tried to determine the causes of severe infection in patients with SSc and to reveal the factors associated with severe infection. We retrospectively examined 214 SSc patients between January 2010 and August 2020. Forty-seven patients with at least one severe infection and 167 patients without severe infection were compared. A total of 76 episodes of severe infections were detected in 47 (22%) patients. Common infections included pneumonia, infected digital ulcer, urinary tract infections, and osteomyelitis. Female patients had a higher frequency in the group without severe infection (91.6% vs. 80.9%, p = 0.035). Patients with severe infections had a higher frequency of digital ulcers (p < 0.001), cardiac (p = 0.002), and GIS involvement (p < 0.001). In multivariable analysis, digital ulcer presence (OR: 2.849 [1.356-5.898] (p = 0.006) and cardiac involvement (OR: 2.801 [1.248-6.285]) were associated with severe infection. Of the patients with severe infections, 34% had recurrent severe infections. There was no difference in demographic and clinical characteristics between patients with recurrent and nonrecurrent severe infections. The presence of digital ulcer and cardiac involvement seem to be associated with a severe infection in patients with systemic sclerosis. In patients with cardiac involvement and digital ulcers, more careful attention may be required for the development of severe infections.