Objectives: Central sensitivity syndrome (CSS) comprises various symptoms caused by central sensitisation (CS). Using the central sensitisation inventory (CSI), a screening questionnaire developed for detecting CSS, this syndrome was recently identified in patients with long-standing rheumatoid arthritis (RA). However, the descriptors of CS-related pain and the effects of CSS on symptoms in patients with rheumatoid arthritis (RA) remain unknown. We examined the characteristics of pain and influence of CSS on patient and evaluator global assessment among multiple clinical variables.
Methods: We used the central sensitisation inventory (CSI) and short-form McGill pain questionnaire to evaluate CSS and characteristics of pain in 240 outpatients with RA. Disease activity, fibromyalgia, neuropathic pain, anxiety, depression, pain catastrophising, and health-related quality of life were evaluated. We used multivariate analysis to analyse the characteristics of CS-related pain according to CSI and the effect of CSS on patient global assessment (PGA), evaluator global assessment (EGA), and PGA minus EGA among relevant clinical variables.
Results: In patients with RA, the main descriptors of pain according to severity of CSI scores were "sharp" and "stabbing", whereas those of pain according to disease activity were "tender" and "throbbing". CSS was associated with EGA (p=0.000, β=- 0.199) and PGA minus EGA (p=0.021, β=0.147), but not with PGA.
Conclusions: In patients with RA, descriptors for CS-related pain differ from those for disease activity-related pain. CSS may have an important impact on EGA and PGA minus EGA. Additionally, CSI may be helpful in identifying why there is discordance between PGA and EGA.