POS0878 ULTRASOUND ASSESSMENT OF DERMAL THICKNESS AND SKIN STIFFNESS IN UNDIFFERENTIATED CONNECTIVE TISSUE DISEASE AT RISK FOR SYSTEMIC SCLEROSIS
Authors: T. Santiago, M. Luis, J. Lima, C. Gaspar, M. J. Salvador, J. A. P. Da Silva
Journal: Annals of the Rheumatic Diseases (2021)

Background: High-frequency ultrasound (HFUS) and shear-wave elastography (SWE) allow an objective assessment of skin involvement in systemic sclerosis (SSc) patients. 1 Till now it has been applied to patients with established diagnosis. 2,3 However, there is no data concerning its application in Undifferentiated Connective Tissue Disease at risk for SSc (UCTD-risk-SSc), i.e., patients with Raynaud’s phenomenon and either SSc marker autoantibodies or typical capillaroscopic findings or both, not satisfying classification criteria for SSc. 4 Objectives: To compare ultrasound-dermal thickness (DT) and skin stiffness, using high-frequency ultrasound and shear-wave elastography, in UCTD-risk-SSc and healthy controls. Methods: Forty UCTD-risk-SSc patients and 40 age- and gender-matched healthy controls were included. Ultrasound-DT was measured using an 18MHz probe, and skin stiffness (i.e. shear-wave velocity values, SWV) using the VTIQ software with a 9MHz probe, at the 17 Rodnan skin sites. The mRSS score was, by definition, zero in all sites, both in cases and controls. Continuous data were expressed as the mean (SD), and Mann-Whitney U test was performed to compare differences between the groups, as variables were not normally distributed. Associations between variables were analysed using the Spearman’s correlation. Results: SWV values were significantly higher in patients with UCTD-risk-SSc compared with controls at the right and left hands, and in the right and left fingers (table 1). Higher values of ultrasound dermal-thickness were found in the fingers and hands bilaterally, although differences were only significantly at the hands, compared with healthy controls (table 1). There were no significant differences in the other Rodnan skin sites. There was no significant correlation between ultrasound-dermal thickness and stiffness at the same skin site. Conclusion: This study provides the first evidence suggesting that ultrasound-DT and stiffness can discriminate patients with UCTD-risk-SSc from healthy controls. Prospective studies including a larger number of patients with different subsets of UCTD-risk-SSc are needed to investigate diagnostic and prognostic value of the ultrasound parameters in this group. References: [1]Santiago T, et al. Arthritis Care Res (Hoboken). 2019;71:563-574. [2]Hesselstrand R, et al. Rheumatology (Oxford). 2008;47:84-7. [3]Flower V et al. jrheum.200234. [4]Valentini, G., et al. Arthritis Care Res, 66: 1520-1527. Table 1. Clinical and ultrasound parameters in UCTD-risk-SSc and healthy control groups. UCTD-risk-SSc (n=40 ) Healthy controls (n=40 ) p value Age, mean (SD) 51.4 (14.9) 49.8 (13.9) Ns Female, n (%) 36 (90.0) 36 (90.0) Raynaud phenomenon, % 100.0% - ANAs 100.0 - Anti-centromere, % 60.0 Anti-Scl70+, % 11.5 Scleroderma/non-scleroderma pattern in capillaroscopy, % 5.0/95.0 - - Ultrasound parameters Dermal thickness (mm ) Dorsal hand right 0.77 (0.32) 0.62 (0.12) 0.02 Dorsal hand left 0.79 (0.39) 0.62 (9.13) 0.02 Proximal phalanx right 0.64 (0.14) 0.61 (0.11) Ns Proximal phalanx left 0.66 (0.16) 0.60 (0.09) Ns SWV values (m/s ) Dorsal hand right 1.94 (0.40) 1.61 (0.24) 0.0001 Dorsal hand left 1.82 (0.36) 1.65 (0.25) 0.025 Proximal phalanx right 2.09 (0.60) 1.68 (0.24) 0.001 Proximal phalanx left 2.13 (0.82) 1.66 (0.27) 0.004 Legend: ANA: Antinuclear antibodies; Ns: Non-significant; UCTD: Undifferentiated Connective Tissue Disease; SD: Standard Deviation Disclosure of Interests: None declared