The association of sociodemographic and disease variables with hand function: a Scleroderma Patient-centered Intervention Network cohort study

Objective. Impaired hand function in systemic sclerosis (SSc) is a primary cause of disability and contributes diminished health-related quality of life. The objective of the present study was to evaluate sociodemographic, lifestyle, and disease-related factors independently associated with hand function in SSc. Methods. Patients enrolled in the Scleroderma Patient-centered Intervention Network Cohort who completed baseline study questionnaires between March 2014 and September 2017 were included. Hand function was measured using the Cochin Hand Function Scale (CHFS). Multiple linear regression analysis was used to identify independent correlates of impaired hand function. Results. Among 1193 participants (88% female), the mean CHFS score was 13.3 (SD=16.1). Female sex (standardised regression coefficient, beta (beta)=.05), current smoking (beta=.07), higher BMI (beta=.06), diffuse SSc (beta=0.14), more severe Raynaud's scores (beta=.23), more severe finger ulcer scores (beta=.23), moderate (beta=0.19) or severe small joint contractures (beta=.20), rheumatoid arthritis (beta=0.07), and idiopathic inflammatory myositis (beta=0.06) were significantly associated with higher CHFS scores (more impaired hand function). Consumption of 1-7 alcoholic drinks per week (beta=-0.07) was associated with lower CHFS scores (less impaired hand function) compared to no drinking. Conclusion. Multiple factors are associated with hand function in SSc. The presence of moderate or severe small joint contractures, the presence of digital ulcers, and severity of Raynaud's phenomenon had the largest associations. Effective interventions are needed to improve the management of hand function in patients with SSc.