Predicting anxiety and depression in systemic lupus erythematosus: the role of inflammation, sociodemographic variables and clinical factors

Objectives: Characterizing the contribution of specific pro-inflammatory mediators (analytes) to depression and anxiety in systemic lupus erythematosus (SLE) is a crucial step in illuminating the mechanisms of these disabling symptoms. The aims of this study were to investigate i) the relationship between depression and anxiety symptoms with relevant clinical and sociodemographic variables and neuroinflammation-associated analytes in a cohort of SLE patients, and ii) the ability of models including these sociodemographic, clinical and biological variables to discriminate between SLE patients with and without clinically significant depression or anxiety. Methods: This is a cross-sectional study of baseline data from participants enrolled in a longitudinal study of cognition in SLE (N = 238). We examined the relationship between serum concentrations of a group of analytes associated with neuroinflammation, relevant sociodemographic and clinical variables and i) depression (measured with the Beck Depression Inventory-II) and anxiety (measured with the Beck Anxiety Inventory) scores, as well as between clinically significant depression and anxiety symptoms (defined using cut-off scores validated in SLE) via random forests. We generated model performance statistics from these models using confusion matrices. Results: Depression is most influenced by duration of SLE and, to a lesser extent, concentrations of the analytes MMP-9. Anxiety is most influenced by the analytes NGAL and IFN- Ɣ, with other variables being less influential. The multivariate models exhibited AUCs of 0.85 (depression), 0.77 (anxiety) and 0.82 (both depression and anxiety). Conclusions: The findings of this exploratory study provide potential models predicting depression and anxiety symptoms in SLE. This produces a basis for further research building a conceptual model explaining the mechanisms of these important patient-centered outcomes in SLE.