Clinical and laboratory features dependent on age at onset in Japanese systemic sclerosis

To clarify those clinical characteristics dependent on patient age at onset of Japanese systemic sclerosis (SSc). A total of 329 SSc patients treated at Kanazawa University Hospital were enrolled in the study and subsequently categorized into four subgroups depending on age at SSc onset: childhood-onset, young-onset, normal age-onset, and late-onset. The clinical features at the first visit were compared between groups. Factors that correlated with age at onset were also analyzed. The childhood-onset subgroup was characterized by a higher male:female ratio, higher anti-topoisomerase I antibody (Ab) and anti-U3 RNP Ab levels, a higher frequency of pitting scars, and a lower frequency of anticentromere Ab and interstitial lung disease (ILD). The young-onset patients had an increased frequency of anti-U1 RNP Ab and anti-U3 RNP Ab, overlap with other connective tissue diseases, digital ulcers, and pitting scars and a reduced frequency of anticentromere Ab. Patients with late-onset SSc showed a shorter disease duration and an increased frequency of anti-RNA polymerase Ab. Multiple regression analysis showed that anti-topoisomerase I Ab, anti-U1 RNP Ab, pitting scars, and long disease duration were associated with onset at a younger age, whereas anticentromere Ab and ILD were associated with onset at an older age. The clinical phenotype of SSc in Japanese patients showed a tendency to be dependent on age at onset.