The Association of Physical Function With Psychosocial Patient‐Reported Outcomes in People With Systemic Lupus Erythematosus

OBJECTIVE: To evaluate how modifiable psychosocial factors and fatigue relate to physical functioning in patients with systemic lupus erythematosus (SLE). METHODS: In this cross-sectional study of two demographically distinct cohorts (Approaches to Positive, Patient-Centered Experiences of Aging with Lupus [APPEAL] and California Lupus Epidemiology Study [CLUES]), perceived physical function was assessed using Patient-Reported Outcomes Measurement Information System Physical Function Short Forms 12a (APPEAL) and 10a (CLUES). Fatigue, depression, and stress; coping efficacy and learned helplessness (APPEAL); and resilience and self-efficacy (CLUES) were all assessed with validated questionnaires. We used multivariable linear regression analyses to assess associations between perceived physical function and outcomes, adjusting for age, sex, and race, then further for disease damage and activity. RESULTS: APPEAL participants (N = 451) were primarily Black (82.5%); CLUES participants (N = 580) were predominantly Asian (29.3%), Hispanic (22.9%), and White (27.4%). Mean physical function T scores were lower in APPEAL (43.6) versus CLUES (47.2; P < 0.05). In both cohorts, higher fatigue, depression, and perceived stress were strongly associated with poorer physical function. Greater resilience (per +1 SD: β = 2.04, 95% confidence interval [CI] 0.57-3.50) and self-efficacy (high vs low: β = 13.53, 95% CI 8.69-18.37) (both in CLUES) and better coping (per +1 SD: β = 3.15, 95% CI 2.39-3.91; in APPEAL) were associated with better physical function. In APPEAL, greater learned helplessness was associated with worse physical function (per +1SD: β = -3.88, 95% CI -4.62 to -3.14). Although adjusting further for disease damage and activity attenuated these associations, they remained statistically significant. CONCLUSION: Our results demonstrate associations of fatigue and psychosocial factors with physical functioning, reinforcing their relationship with overall health in SLE.