The Role of Central Sensitization in Autoimmune Connective Tissue Diseases: A Comparative Cross-Sectional Study.

Objective: To investigate the central sensitization (CS) in patients with autoimmune connective tissue diseases (ACTDs) and its relationship with disease activity, laboratory findings, medical treatments, organ involvements, and comorbidity.

Methods: One hundred and eleven patients with ACTDs and 40 healthy individuals were included. All patients were divided into three groups in terms of their diseases: Sjögren's syndrome (SS), rheumatoid arthritis (RA), and systemic lupus erythematosus (SLE). The CS was assessed using the central sensitization inventory (CSI-A and CSI-B scores). The disease activity, laboratory findings, medical treatments, organ involvements, and comorbidity of all patients were evaluated.

Results: Overall, 41.4% patients with ACTDs had CS. SS group had the highest CS positivity (n = 21, 58.3%) compared to the RA (n = 14, 36.8%) and SLE (n = 11, 29.7%) groups. The SS group had a significantly higher CSI-A score (p < 0.016) than the RA and SLE group, which had similar scores. CSI-A (p = 0.008, r = -0.63) and CSI-B (p = 0.001, r = -0.76) scores were moderately to high correlated with vitamin D3 levels in SLE group. CSI-B score was moderately correlated with folic acid levels (p = 0.03, r = 0.50) and TSH (p = 0.005, r = 0.55) in SS group. The CSI-A score ≥ 40 subgroup had more female gender, frequency of COPD or asthma, more coexisting fibromyalgia, higher VAS score, more common exocrine gland involvement, and higher corticosteroid dose compared to the CSI score < 40 subgroup.

Conclusions: CS is commonly seen in patients with ACTDs, especially in SS. CS is associated with vitamin D3, folic acid, and TSH levels in ACTD subgroups and the patients with clinical CS have a specific profile.