Central sensitization in rheumatoid arthritis and psoriatic arthritis is associated with symptom burden than inflammatory activity: a cross-sectional study.

This study aimed to compare the prevalence and severity of central sensitization (CS) between patients with psoriatic arthritis (PsA) and rheumatoid arthritis (RA). Also, we investigated clinical correlates of CS, its impact on disease burden, and factors associated with CS in these patients. This cross-sectional study was conducted in the Department of Rheumatology outpatient clinic between May 2025 and January 2026. Ninety-three patients with PsA and ninety-two patients with RA meeting were included. CS was assessed using the Central Sensitization Inventory (CSI). Sleep quality was evaluated using the Pittsburgh Sleep Quality Index (PSQI), and neuropathic pain-like symptoms were assessed with the painDETECT questionnaire (PDQ). Multivariable linear regression analyses were performed to examine whether disease diagnosis (RA vs PsA) was independently associated with CSI scores and to identify variables independently related to CS. CS (CSI ≥40) was present in 48.6% of the cohort, and CSI scores were significantly higher in PsA. Patients with CS demonstrated higher tender joint counts, disease activity (DAS28), pain intensity, and patient- and physician-reported global assessments (all p<0.001). Impaired sleep quality and neuropathic pain-like symptoms were also significantly more pronounced in the CS group. CSI scores showed strong correlations with pain intensity, disease activity, tender joint counts, and poor sleep quality. In multivariable regression analysis, poorer sleep quality remained significantly associated with higher CSI scores (B=1.94, 95% CI 1.32-2.55; p<0.001). Fibromyalgia was also independently associated with higher CSI scores (B=11.79; 95% CI 5.57-18.02; p<0.001), whereas disease diagnosis (RA vs PsA), inflammatory markers, and treatment modality were not associated with CSI scores. Central sensitization may develop independently of arthritis phenotype but appears to impose a greater clinical burden in PsA. Early multidimensional evaluation of pain mechanisms, alongside inflammatory activity, may help identify patients at risk and support more comprehensive management strategies in inflammatory arthritis.