Factors Associated with Physical Function among People with Systemic Sclerosis: A Scleroderma Patient-centered Intervention Network (SPIN) Cohort Cross-sectional Study

ObjectivesTo compare physical function in systemic sclerosis (SSc, scleroderma) to general population normative data and identify associated factors. MethodsScleroderma Patient-centered Intervention Network Cohort participants completed the Physical Function domain of the Patient-Reported Outcomes Measurement Information System Version 2 upon enrollment. Multivariable linear regression was used to assess associations of sociodemographic, lifestyle, and disease-related variables. ResultsAmong 2,385 participants, mean physical function T-score (43.7, SD = 8.9) was approximately 2/3 of a standard deviation (SD) below the US general population (mean = 50, SD = 10). Factors associated in multivariable analysis included older age (-0.74 points per SD years, 95% CI -0.78 to -1.08), female sex (-1.35, -2.37 to -0.34), fewer years of education (-0.41 points per SD in years, -0.75 to -0.07), being single, divorced, or widowed (-0.76, -1.48 to -0.03), smoking (-3.14, -4.42 to -1.85), alcohol consumption (0.79 points per SD drinks per week, 0.45 to 1.14), BMI (-1.41 points per SD, -1.75 to -1.07), diffuse subtype (-1.43, -2.23 to -0.62), gastrointestinal involvement (-2.58, -3.53 to -1.62), digital ulcers (-1.96, -2.94 to -0.98), moderate (-1.94, -2.94 to -0.93) and severe (-1.76, -3.24 to -0.28) small joint contractures, moderate (-2.10, -3.44 to -0.76) and severe (-2.54, -4.64 to -0.44) large joint contractures, interstitial lung disease (-1.52, -2.27 to -0.77); pulmonary arterial hypertension (-3.72, -4.91 to -2.52); rheumatoid arthritis (-2.10, -3.64 to -0.56) and idiopathic inflammatory myositis (-2.10, -3.63 to -0.56). ConclusionPhysical function is impaired for many individuals with SSc and associated with multiple disease factors. KEY MESSAGESO_LIIndividuals with systemic sclerosis (SSc) face many challenges that can impact their physical function C_LIO_LILevels of physical function in individuals with SSc are impaired compared to the general population C_LIO_LIMultiple disease factors are significantly associated with worse physical function in SSc C_LI