Objective: Pain in rheumatoid arthritis (RA) is considered to be associated with non-inflammatory factors, including physical disabilities, psychiatric disorders, and pain catastrophizing (PC). PC is reportedly a key driver in the development of pain in patients with RA without clinical signs of inflammation; however, previous studies enroled patients with RA who were potentially in an inflammatory state. Hence, our aim was to investigate the role of PC as the possible link between pain, physical disabilities, and psychiatric disorders in patients with RA without clinical signs of inflammation.
Materials and methods: In this cross-sectional study, 81 patients with RA without clinical signs of inflammation were included; all patients had serum C-reactive protein levels <0.5 mg/dL, without any inflammatory joints. We examined the demographic and clinical data and administered the pain visual analogue scale (VAS), pain catastrophizing scale (PCS), Health Assessment Questionnaire Disability Index (HAQ-DI), and patient version of the Brief Scale for Psychiatric Problems in Orthopaedic Patients (pBS-POP). A series of multivariate-adjusted multiple regression analyses were performed to examine the associations between PC and pain intensity, physical disabilities, and psychiatric disorders.
Results: We found associations between all the above-mentioned variables in separate models with HAQ-DI, pBS-POP, and PCS scores. However, in the model associated with pain VAS, the PCS score (β = 0.34, p = 0.0073) emerged as the only variable showing a statistically significant association.
Conclusions: PC is associated with pain in patients with RA without clinical signs of inflammation, and this association may be mediated through pathways involving physical disabilities and psychiatric disorders.
Keywords: non-inflammatory cause of pain; pain catastrophizing; physical disability; psychiatric disorder; rheumatoid arthritis.
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