The neuropathic pain features in Psoriatic Arthritis: a cross-sectional evaluation of prevalence and associated factors

OBJECTIVE: To evaluate the prevalence and factors associated with the neuropathic pain features in a cohort of patients with psoriatic arthritis (PsA). METHODS: A cross-sectional evaluation was conducted in consecutive patients suffering from PsA with prevalent peripheral joint involvement, referring to three rheumatological centers. For each patient a comprehensive assessment of disease activity, physical function, and disease impact was carried out. The presence of comorbid fibromyalgia syndrome (FMS) was evaluated. Acute phase reactants were also recorded. The neuropathic pain features were investigated through the PainDETECT Questionnaire (PDQ). A logistic regression analysis was therefore conducted using the PDQ as dependent variable. RESULTS: The final evaluation included 118 patients. A comorbid FMS was detectable in 30 of the 118 PsA patients (25.4%). Probable characteristics of neuropathic pain (PDQ ≥19) were found in 30 (25.4%) patients overall, ambiguous (PDQ >12 and <19) in 21 (17.8%) patients, and unlikely (PDQ ≤12) in 67 (56.8%) patients. Using logistic regression analysis, the only independent variable among those investigated able to explain the neuropathic pain features investigated by PDQ was the presence of a comorbid FMS (p = 0.0127). Excluding patients with comorbid FMS, an association with disability (measured by Health Assessment Questionnaire - Disability Index) emerges (p = 0.0489). In patients with PsA and comorbid FMS, PDQ scores were significantly higher than in patients without comorbid FMS. CONCLUSION: Neuropathic pain features are common in PsA patients, and the presence of pain sensitization (comorbid FMS) seems to be its main predictor.