Predictors of radiographic severity and functional disability in Turkish patients with ankylosing spondylitis

The objective of this study is to investigate the association between clinical and laboratory prognostic factors, radiographic severity, and functional limitations in Turkish patients with ankylosing spondylitis (AS). One hundred and two patients with AS were included in this study (66 male patients, 65%). All the necessary information regarding predictor variables, including clinical features, social status, and treatment regimens, were recorded diligently. Their spinal mobility was measured, and then, their disease activities were evaluated by using the Bath Ankylosing Spondylitis Disease Activity Index. Radiological damage (Bath Ankylosing Spondylitis Radiology Index, BASRI) and functional disability (Bath Ankylosing Spondylitis Functional Index, BASFI) were used to evaluate the outcome measures of AS. The male to female ratio was 1.8. Average age at symptom onset was 23.9 ± 28.24 years (6-54 years), and average disease duration was 16.15 ± 10.62 years. Occiput-to-wall distance, hand-to-floor distance, and the modified Schober's test results were worse in males. Hip involvement was more common in male patients, and all radiological measurements were worse in male patients than in the female ones. Disease duration, male sex, and renal stone occurrence were associated with higher radiological score. Erythrocyte sedimentation rate and the disease activity score were associated with high BASFI scores. Higher CRP levels and hip involvement were both associated with high BASRI and BASFI scores. Radiological hip involvement was determined to be an inauspicious predictor for AS (p < 0.0001). We determined a strong association of hip involvement, increased CRP levels, and renal stone history with severe radiographic damage. Hip involvement, disease duration, ESR, CRP levels, and lower socioeconomic status were all associated with a higher BASFI score.