High burden of skin sclerosis is associated with severe organ involvement in patients with systemic sclerosis and systemic sclerosis overlap syndrome.

The objective of this study is to investigate the impact of skin sclerosis burden on an internal organ involvement over a 1-year period, as measured by time-adjusted accrual-modified Rodnan skin score (TA-mRSS), and to evaluate association between TA-mRSS patterns and laboratory tests in patients with systemic sclerosis (SSc). This prospective study was conducted at Siriraj Hospital (Bangkok, Thailand) during the November 2013-November 2016. SSc patients by ACR/EULAR 2013 or ACR 1980 criteria were eligible. TA-mRSS was classified as low, intermediate, or high, and then compared between groups. Correlation between the arithmetic mean of laboratory tests and TA-mRSS was assessed by multiple linear regression analysis. A total of 118 patients, with 81.4% women, median (IQR) age 49.8 (43.8, 55.1) years, disease duration from onset of non-Raynaud symptoms to first visit of 3.3 (1, 6.8) years, 78% dcSSc, and 75.3% anti-Scl-70 positivity, were analyzed. TA-mRSS over 1 year ranged from 0 to 37.44. The high skin sclerosis burden group had a median TA-mRSS > 7.26 (> 67th percentile). Patients with high TA-mRSS were dcSSc, high initial and average mRSS, and had tendon friction rub, digital ischemic complications, usual interstitial pneumonia, diastolic dysfunction, gastrointestinal dysmotility, and low serum albumin. In multiple linear regression analysis, the arithmetic mean of hemoglobin (B = - 1.007, 95% CI - 1.779 to - 0.236), erythrocyte sedimentation rate (B = - 0.078, 95% CI - 0.126 to - 0.029), serum glutamic oxaloacetic transaminase (B = 0.073, 95% CI 0.026-0.12), creatine phosphokinase (B = 0.012, 95% CI 0.003-0.021), and albumin (B = - 4.117, 95% CI - 6.958 to - 1.276) were associated with TA-mRSS. This study found a higher cumulative course of mRSS over a 1-year period to be significantly associated with severe internal organ involvement.