Predictors of clinical features in early‐onset severe systemic sclerosis: An analysis from a multicenter prospective observational Japanese cohort

As the clinical course of systemic sclerosis (SSc) varies widely, prognostic indicators have been sought to predict the outcomes of individual patients. Racial differences in SSc render it necessary to validate prognostic indicators in different patient cohorts. In this study, we aimed to assess clinical and laboratory parameters in Japanese patients with early-stage SSc with diffuse cutaneous involvement and/or interstitial lung disease, and identify predictive factors for disease progression. We performed multivariate analyses of baseline clinical information to estimate symptoms 4 years later in Japanese patients with diffuse cutaneous SSc and/or SSc with interstitial lung disease. Patients were enrolled in the study within 5 years of disease onset at 10 Japanese SSc centers. Over 12 years, 115 patients followed up for 4 years were included in this study. The modified Rodnan skin score (mRSS) at 4 years correlated with the baseline mRSS and finger-to-palm distance, defined as the average length from the distal tip of the fourth finger to the distal palmar crease. The percentage predicted vital capacity (%VC) in year 4 positively and negatively correlated with initial %VC and the presence of anti-topoisomerase I antibodies, respectively. The Health Assessment Questionnaire Disability Index (HAQ-DI) at 4 years was positively and negatively associated with baseline HAQ-DI and %VC, respectively. The occurrence of digital ulcers within 4 years was associated with the initial presence of digital ulcers, finger-to-palm distance, and the presence of digital pitting scars and anti-topoisomerase I antibodies. This study identified several factors that may predict the progression of early-stage SSc in Japanese patients. Finger-to-palm distance may be a useful tool for predicting the progression of skin thickening and the development of digital ulcers in the early stages of severe SSc, but larger, long-term prospective studies are needed to confirm our findings.