Fig. 1

The flow chart of patient recruitment. All Japanese patients with systemic sclerosis (SSc) hospitalized to our clinic for initial evaluation were collected. Patients who did not meet the classification criteria for SSc established by American College of Rheumatology and European League Against Rheumatism in 2013 (ACR/EULAR criteria 2013) were excluded. In total, 198 patients were recruited into our study