Somatosensory dysfunction related neuropathic pain component affects disease activity, functional status and quality of life in ankylosing spondylitis

Aim To investigate the neuropathic pain (NP) component in ankylosing spondylitis (AS) and to assess the relations between NP and disease characteristics. Methods Eighty participants were included in this study. Demographic properties, duration of disease, laboratory values and clinical assessments (visual analog scale [VAS], Bath Ankylosing Spondylitis Disease Activity Index [BASDAI], Bath Ankylosing Spondylitis Functional Index [BASFI], Bath Ankylosing Spondylitis Metrology Index [BASMI], Short Form [SF]-36 questionnaire, Beck Depression Inventory [BDI]) were recorded. The NP component was assessed by both DN4 and PainDETECT questionnaires (PD-Q) and patients were classified into groups according to questionnaire scores. Results NP component was detected by the DN4 and PD-Q in 40% and 28.7% of our patients, respectively. Likely-NP group had significantly higher scores in VAS-pain, BASDAI, BASFI, BASMI and BDI compared with both uncertain-NP and unlikely-NP groups. There was no significant difference between the SF-36 scores of the likely-NP and uncertain-NP groups. Moreover, all SF-36 scores were significantly lower in the likely-NP group than in the unlikely-NP group. Based on DN4 scale, patients with NP had significantly higher erythrocyte sedimentation rate (ESR), VAS, BASDAI, BASFI, BASMI scores and significantly lower SF-36 (except social functioning) scores compared to patients without NP. Both painDETECT and DN4 scores of the patients were significantly positively correlated with ESR, VAS, BASDAI, BASFI, BASMI, BDI scores and negatively correlated with all SF-36 scores. Conclusions Our results revealed that the presence of NP component in patients with AS is associated with various disease-related variables, including pain, high disease activity, reduced mobility of the axial skeleton, depression and poor quality of life.