Reduction of fat free mass index and phase angle is a risk factor for development digital ulcers in systemic sclerosis patients

Introduction/objectives This study aims to evaluate the role of fat free mass index (FFMI) and phase angle (PhA) as markers to predict occurrence of new digital ulcers in systemic sclerosis (SSc) patients. Methods Body composition evaluation from bioelectrical impedance and clinical assessment were performed in SSc patients at enrollment and after 12 months follow-up. Results Seventy-nine SSc patients (67 female) with a mean age of 53 ± 13 years were enrolled. In SSc patients with a digital ulcers history, FFMI value is lower ( p < 0.05) and phase angle (PhA) value is higher ( p < 0.01) than SSc patients without a digital ulcers history. After 12 months of follow-up, 30 patients (38%) presented at least one new episode of digital ulcers. Patients with reduced FFMI had a relative risk of 6.7 for new digital ulcers (CI 2.1–21.8, p < 0.001). Patients with reduced PhA had a relative risk of 10.1 for new digital ulcers (CI 3.5–29.5, p < 0.0001). In multivariate analysis, FFMI and PhA were associated with major vascular complication (digital ulcers, pulmonary arterial hypertension, and scleroderma renal crisis). FFMI loss, assessed as delta between follow-up and baseline, is higher in SSc with short duration (≤ 3 years) than SSc patients with long duration [0.4 (0–0.50) vs − 0.10 (− 0.2–0)]. Conclusion In SSc patients, reduction of the FFMI and PhA represents after 12 months a risk factor for development of new digital ulcers and major vascular complication. Key Points • Fat free mass index represents a risk factor for development of digital ulcers • Phase angle represents a risk factor for development of digital ulcers • Body compositions in systemic sclerosis are a marker of activity disease