Neuropathic Pain-Like Features in Patients With Rheumatoid Arthritis and Spondyloarthritis Receiving Targeted Therapies: Prevalence and Associated Factors

Persistent pain despite targeted therapy remains a major challenge in patients with rheumatoid arthritis (RA) and spondyloarthritis (SpA), and neuropathic pain-like features may contribute to this residual pain.We conducted a cross-sectional study including 155 patients receiving biologic or targeted synthetic diseasemodifying antirheumatic drugs (bDMARDs or tsDMARDs; 78 RA and 77 SpA) to determine the prevalence of neuropathic pain-like features and identify associated clinical factors.Neuropathic pain-like features were screened using the Douleur Neuropathique 4 (DN4) and painDETECT questionnaires.Univariable logistic regression analyses were performed separately for each disease group, followed by parsimonious multivariable models including functional impairment, disease activity, and current pain intensity.Neuropathic pain-like features (DN4 ≥4) were identified in 19 (24.4%) patients with RA and 21 (27.3%)patients with SpA, with no statistically significant between-group difference (p = 0.679).Although median painDETECT scores were significantly higher in SpA, the distribution of painDETECT categories did not differ significantly between the two groups.In univariable analyses, Health Assessment Questionnaire (HAQ) and current pain visual analogue scale (VAS) were significantly associated with DN4 positivity in RA, whereas Bath Ankylosing Spondylitis Functional Index (BASFI), Ankylosing Spondylitis Disease Activity Score using C-reactive protein (ASDAS-CRP), and current pain VAS were significantly associated with DN4 positivity in SpA.In multivariable analyses, current pain intensity remained significantly associated with DN4 positivity in both disease groups: pain VAS in RA (adjusted OR 2.77, 95% CI 1.54-4.98;p < 0.001) and SpA (adjusted OR 1.90, 95% CI 1.26-2.88;p = 0.002).The adjusted associations with functional impairment and disease activity did not reach statistical significance in either disease group.Neuropathic pain-like features were frequently identified in patients with RA and SpA receiving targeted therapies and were significantly associated with greater pain intensity after adjustment.Associations with functional impairment and inflammatory disease activity remained uncertain after adjustment.These findings support a comprehensive assessment of persistent pain in patients receiving targeted therapies.