Fatigue: an overlooked determinant of physical function in scleroderma.

OBJECTIVES To examine the frequency and correlates of fatigue and its impact on physical and social functioning in patients with scleroderma, and to investigate whether fatigue mediates an association between pain and physical function. METHODS One hundred and seven scleroderma patients attending an academic scleroderma specialty centre completed measures of fatigue, sleep, pain, depressive symptoms, and physical and social functioning. Patients had received a comprehensive clinical assessment with a diagnosis of limited or diffuse scleroderma from their attending rheumatologist. RESULTS In this sample of scleroderma patients, 76% reported experiencing fatigue and 61% of these patients reported fatigue as one of their three most distressing symptoms. Patients endorsing greater pain had higher levels of self-reported fatigue, as did those reporting greater depression and poorer functioning. Multiple regression analyses indicated that global fatigue was a significant cross-sectional correlate of physical, but not social, functioning after controlling for depressive symptoms, level of education, poor sleep quality and disease subtype. However, global fatigue did not predict physical function when pain was included in the analyses. CONCLUSIONS Our findings indicate that fatigue is common in scleroderma and that pain and fatigue are significant determinants of physical functioning for patients with limited and diffuse disease subtypes. Future research should investigate whether effective pain treatments reduce symptoms of fatigue, as well as identify other possible causes of fatigue in order to improve quality of life for scleroderma patients.