Digital ulcers score: A scoring system to assess digital ulcers in patients suffering from systemic sclerosis

Objective. To develop a standardised scoring system to assess the severity of DUs in SSc patients and correlate it with functional outcomes. Methods. In this cross-sectional, longitudinal study in SSc patients with DUs (n=65) we developed a Digital Ulcers score (DUS) for the assessment of DUs. DUS and the ABILHAND score were measured at each visit and differences were analysed using Tamhane's T2 test. Spearman's Rho test was applied for correlational analysis of DUS and functional outcomes. We calculated a linear regression model using clustered standard errors for correlation analysis between DUS and ABILHAND over time. Results. 117 assessments of DUS were performed in 65 SSc patients. Mean DUS was 11.6±1.9 (range: 0-68). Subgroup analyses showed a higher DUS in patients suffering from diffuse cutaneous SSc when compared to patients with limited cutaneous SSc (12.8±3.0 vs. 9.7±2.2 p=0.18). There was no correlation between the DUS and manual ability using the ABILHAND score (overall: n=106 r=-0.138, p=0.22). We observed a small but significant linear correlation between the DUS and the ABILHANDscore for a single patient over time (n=14, R2=0.31, r=0.06, p=0.02). Conclusion. The DUS is a feasible scoring instrument to assess severity of DUs in SSc patients. In accordance with the literature the severity of DUs correlates with clinical parameters but also severity of the disease. Further study is needed to establish the DUS as a standardised tool for the assessment of DUs.