Fatigue in patients with systemic lupus erythematosus and neuropsychiatric symptoms is associated with anxiety and depression rather than inflammatory disease activity.

Introduction: We aimed to investigate risk factors for fatigue in patients with systemic lupus erythematosus (SLE) and neuropsychiatric symptoms in order to identify potential interventional strategies.

Methods: Patients visiting the neuropsychiatric SLE (NPSLE) clinic of the Leiden University Medical Center between 2007-2019 were included. In a multidisciplinary consensus meeting, SLE patients were classified as having neuropsychiatric symptoms of inflammatory origin (inflammatory phenotype) or other origin (non-inflammatory phenotype). Fatigue was assessed with the SF-36 vitality domain (VT) since 2007 and the multidimensional fatigue inventory (MFI) and visual analogue scale (VAS) since 2011. Patients with a score on the SF-36 VT ≥1 standard deviation (SD) away from the mean of age-related controls of the general population were classified as fatigued; patients ≥2 SD away were classified as extremely fatigued. Disease activity was measured using the SLE disease activity index-2000. The influence of the presence of an inflammatory phenotype, disease activity and symptoms of depression and anxiety as measured by the hospital anxiety and depression scale (HADS) was analyzed using multiple regression analyses corrected for age, sex and education.

Results: 348 out of 371 eligible patients filled in questionnaires and were included in this study . The majority was female (87%) and the mean age was 43 ± 14 years. 72 patients (21%) had neuropsychiatric symptoms of an inflammatory origin. Fatigue was present in 78% of all patients and extreme fatigue was present in 50% of patients with an inflammatory phenotype vs 46% in the non-inflammatory phenotype. Fatigue was similar in patients with an inflammatory phenotype compared to patients with a non-inflammatory phenotype on the SF-36 VT (β: 0.8 (95% CI -4.8; 6.1) and there was less fatigue in patients with an inflammatory phenotype on the MFI and VAS (β: -3.7 (95% CI: -6.9; -0.5) and β: -1.0 (95% CI -1.6; -0.3)). There was no association between disease activity and fatigue, but symptoms of anxiety and depression (HADS) associated strongly with all fatigue measurements.

Conclusion: This study suggests that intervention strategies to target fatigue in (NP)SLE patients may need to focus on symptoms of anxiety and depression rather than immunosuppressive treatment.