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

ABSTRACT Objectives To compare physical function in systemic sclerosis (SSc, scleroderma) to general population normative data and identify associated factors. Methods Scleroderma 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. Results Among 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). Conclusion Physical function is impaired for many individuals with SSc and associated with multiple disease factors. KEY MESSAGES Individuals with systemic sclerosis (SSc) face many challenges that can impact their physical function Levels of physical function in individuals with SSc are impaired compared to the general population Multiple disease factors are significantly associated with worse physical function in SSc