Association of inflammatory markers with depression and anxiety in female patients with primary Sjögren’s syndrome

Primary Sjögren's syndrome (pSS) is a chronic autoimmune disease affecting exocrine glands and is frequently accompanied by depression and anxiety. Proinflammatory cytokines, particularly interleukin 6 (IL-6), have been implicated in the pathogenesis of both pSS and mood disorders. This study aimed to assess the association between inflammatory markers, disease activity, and psychological symptoms in patients with pSS. A cross-sectional study was conducted on 60 female patients diagnosed with pSS at Sestre milosrdnice University Hospital Center between 2019 and 2021. Depression and anxiety were evaluated using the Hospital Anxiety and Depression Scale. Inflammatory biomarkers (erythrocyte sedimentation rate, rheumatoid factor, ferritin, fibrinogen, CRP, C3, C4, IL-6) and disease activity indices (ESSDAI, ESSPRI) were analyzed. Statistical analyses, including logistic regression, were applied to determine independent predictors of depression and anxiety. Depression was detected in 39/60 of patients, while 34/60 exhibited anxiety symptoms. Patients with either depression or anxiety had significantly higher IL-6 concentration (P < 0.001 and P = 0.002, respectively). Logistic regression identified IL-6 as an independent predictor of depression (OR = 3.23, 95%CI: 1.07 - 9.80, P = 0.038), while ESSPRI fatigue was a significant predictor of anxiety (OR = 2.01, 95%CI: 1.13 - 3.58, P = 0.018). The findings suggest that IL-6 could be a predictor of pSS-related depression, potentially serving as a biomarker for this extraglandular manifestation and ESSPRI fatigue as a predictor for anxiety.