Abstract
OBJECTIVE: To define biopsychosocial mechanisms of pain that go above and beyond disease activity and organ damage in systemic lupus erythematosus (SLE). METHODS: We conducted a cross-sectional analysis of patient-reported data in a population-based registry of 766 people with SLE. Predictors of pain intensity and interference were examined using hierarchical linear regression. We built 2 main hierarchical regression models with pain intensity and interference as outcomes, both regressed on disease activity and organ damage. For each model, we sought to establish the relationship between pain outcomes and the primary exposures using sequential steps comprising the inclusion of each construct in 6 stages: demographic, socioeconomic, physical, psychological, behavioral, and social factors. We also conducted sensitivity analyses eliminating all overt aspects of pain in the disease activity measure and reestimated the models. RESULTS: Disease activity and organ damage explained 32-33% of the variance in pain intensity and interference. Sociodemographic factors accounted for an additional 4-9% of variance in pain outcomes, whereas psychosocial/behavioral factors accounted for the final 4% of variance. In the sensitivity analyses, we found that disease activity and organ damage explained 25% of the variance in pain outcomes. CONCLUSION: Disease activity only explained 33% of the variance in pain outcomes. However, there was an attenuation in these associations after accounting for psychosocial/behavioral factors, highlighting their roles in modifying the relationship between disease activity and pain. These findings suggest that multilevel interventions may be needed to tackle the negative effect of pain in SLE.