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

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.

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.

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.

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.