CRP and ankylosing spondylitis: The average age of the AS patients was between 24.8 and 52.13 years, the proportion of males ranged from 0 to 100%, the average disease duration was from 1.6 to 13.3 years, the average erythrocyte sedimentation rate (ESR) was from 15.2 to 57.3 mm/hour, the average C-reactive protein (CRP) was from 6.63 to 77.1 mg/l, and the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) [28] from was 1.19 to 51.94.