CRP and ankylosing spondylitis: r-axSpA; radiographic axial spondylarthritis, HLA-B27; Human leukocyte antigen B27, NSAID; non-steroidal anti-inflammatory drug, cDMARDS; conventional disease-modifying antirheumatic drugs, bDMARDS; biological disease-modifying antirheumatic drugs, TNFi; tumour necrosis factor inhibitor, IL17i; Interleukin-17 inhibitor, ASDAS; Ankylosing Spondylitis Disease Activity Score, CRP; C-reactive protein.