Background Joint involvement is frequent and strongly contributes to impaired quality of life in systemic sclerosis (SSc). In a previous cross-sectional study, synovitis and tendon friction rubs were associated with systemic inflammation and disease activity.
Objectives Therefore, the aim of the present study was to determine whether synovitis and tendon friction rubs may predict disease progression and severity.
Methods We included patients from the EUSTAR database (MEDS online) with early disease duration (first non Raynaud’s symptom equal or less than 3 years) and with a follow-up of at least two years. We extracted data regarding the presence or not of synovitis (tender and swelling joints) and tendon friction rubs (rubbing sensation detected as the tendon was moved) and data related to disease progression. Skin progression was defined by a ≥10% worsening of the modified Rodnan skin score (mRSS). Pulmonary progression was defined by the new onset of pulmonary fibrosis on high resolution CT scan, or the deterioration of lung volume (≥10% of forced vital capacity, FVC). Cardio-vascular worsening was defined for skin by new ischemic digital ulcers (DU), for lung by pre-capillary pulmonary arterial hypertension (PAH) on right heart catheterization, and for heart by the reduction of the left ventricular ejection fraction below 50%. Renal progression was defined by the occurrence of scleroderma renal crisis.
Results From the 9165 patients included in the database, 1301 patients (1079 females) met our inclusion criteria (mean ± SD age of 55±15 years, mean ± SD follow-up: 4.5±2.2 years).
Synovitis was identified as a predictor of skin progression (Log-rank test, p=0.008). Synovitis remained predictive of skin progression after stratification for disease subset and autoantibody status (Hazard Ratio, HR: 2.39, 95% confidence interval, CI: 1.4-4.98). No impact on lung outcomes was identified.
Synovitis predicted vascular progression both for the occurrence of new ischemic DU in the whole cohort of SSc patients (p=0.005), and in the subset of patients without history of DU at baseline (p=0.005), such as development of PAH (p=0.03) and left ventricular dysfunction (p=0.003).
Tendon friction rubs predicted skin progression (p=0.02), PAH (p=0.001) and scleroderma renal crisis (p=0.003).
Conclusions This first report of the prospective follow-up of EUSTAR patients identified for the first time the merit of baseline synovitis and extended previous data for tendon friction rubs in early SSc patients.
These results obtained through the largest worldwide database support the use of these easily detected clinical findings for the risk stratification of SSc patients. These parameters might be used in the future to select high-risk patients, guide therapies and might be regarded as potential surrogate markers for severity.
Disclosure of Interest: None Declared