General linear models were used to explore clinical differences in disease activity (Bath Ankylosing Spondylitis Disease Activity Index [BASDAI]), activity limitations (Bath Ankylosing Spondylitis Functional Index [BASFI]), fear of movement (Tampa Scale for Kinesiophobia 11-item version [TSK-11]), anxiety (Hospital Anxiety and Depression Scale subscale anxiety [HADS-A]) and depression (HADS subscale depression [HADS-D]) between four subgroups classified by widespread non-articular pain (WNAP+/-) and physician global assessment of disease activity (PGDA+/-) (p < .05).
Kinesiophobia was assessed with the Tampa Scale for kinesiophobia (TSK: Activity Avoidance-TSK1 and Harm-TSK2 subscales); anxiety and depression were assessed with STAI and BDI, respectively, and preoperative pain and function, sex, age, BMI, education level, number of painful joints and years of symptoms' duration before surgery were documented as well.