CRP and ankylosing spondylitis: Various demographic characteristics (age, sex), body mass index, laboratory tests (HLA-B27, CRP), disease characteristics (disease course, BASDAI, Bath ankylosing spondylitis functional index(BASFI), patient global assessment(PGA), 36-item short-form(SF-36), uveitis, inflammatory bowel disease, and/or psoriasis history, joint tenderness, and swelling count), medication history and other 27 clinical factors were used as potential predictive factors, and the improvement in ankylosing spondylitis disease activity score(ASDAS) score was used as the outcome indicator.