Fatigue levels and associated factors in systemic sclerosis: a cross-sectional study of 2,385 SPIN Cohort participants

Objectives To compare fatigue in a large multinational systemic sclerosis (SSc) cohort to general population data and identify associated sociodemographic, lifestyle and SSc disease factors. Methods Scleroderma Patient-centered Intervention Network Cohort participants completed the Patient-Reported Outcomes Measurement Information System-29 v2.0 fatigue domain. T-scores were compared with the USA general population (mean = 50; SD = 10). Multivariable linear regression was used to assess associations with sociodemographic, lifestyle, and disease-related variables. Results Among 2,385 participants (mean age 54.9 (SD = 12.6) years, 87% female, 38% diffuse SSc), mean fatigue T-score was 54.6 (SD = 11.0); 438 (18%) reported mild fatigue, 641 (27%) moderate, and 180 (8%) severe fatigue. Fatigue was independently associated with sociodemographic factors age (-0.10 points per year, [95% CI -0.14;-0.07]), male sex (-1.67 points, [-2.96;-0.37]), non-married status (0.97 points [0.04; 1.89]), and country (reference USA; France -2.35 points [-3.48;-1.21] and UK 2.38 points [0.80; 3.97]), and lifestyle factors smoking (4.16 points [2.52; 5.80]), alcohol consumption (-0.18 points per drink per week [-0.28;-0.07]), and body-mass index (0.34 points per unit [0.27; 0.42]). Fatigue was associated with disease-related factors gastrointestinal involvement (4.21 points [2.99; 5.43]), digital ulcers (1.51 points, [0.25; 2.77]), moderate small joints contractures (1.41 points [0.13; 2.69]), rheumatoid arthritis (4.34 points [2.37–6.31]) and Sjögren’s syndrome (1.89 points [0.23; 3.55]). When pain was included in the model, its association was large (2.19 points [2.03; 2.34]) and interstitial lung disease was also associated (1.21 points [0.42; 2.00]). Conclusions In people with SSc, fatigue scores were substantially higher than the general population and associated with multiple disease factors including gastrointestinal involvement, several painful disease manifestations, and lung involvement.