Inflammatory or Neuropathic Pain: Characteristics and Their Relationships with Disease Activity and Functional Status in Axial Spondyloarthritis Patients

Objective. To assess inflammatory back pain (IBP) and neuropathic pain (NP) in patients with axial spondyloarthritis (axSpA) and explore their relationships with disease activity and functional status. Design. Descriptive, cross-sectional study. Setting and Subjects. A convenience sample of 132 patients with axSpA was recruited from a university-affiliated hospital in China. Methods. The presence of IBP or NP, pain intensity and quality, pain interference, disease activity, and functional status were assessed. Univariate analyses and binary logistic regressions were used to identify factors related to IBP or NP. Results. Fifty patients (37.9%) had IBP, and 22 (16.7%) had NP. Scores of pain intensity and pain interference, disease activity, and functional limitation were significantly higher in patients with IBP or NP than those without either (P< 0.05). The quality of IBP or NP was mainly presented as sensory descriptors, and patients with IBP had a higher level of "tiring-exhausting" in affective descriptors (P< 0.05). There was a significant correlation between IBP and disease activity (odds ratio (OR) = 1.813, 95% confidence interval (CH = 1.196-2.750). NP was related to functional limitation (OR = 1.544, 95% CI = 1.098-2.171). Conclusions. Though pain quality (sensory and affective pain descriptors) show differently in patients with IBP or NP, the axSpA patients with IBP or NP experience more severe pain intensity and pain interference, higher disease activity, and greater functional limitation. The presence of IBP or NP could reflect higher disease activity or greater functional limitation in patients with axSpA.