CRP and ankylosing spondylitis: Previous research has demonstrated the strong convergent and discriminative validity of the Assessment of Spondyloarthritis International Society Health Index (ASAS-HI) with established measures such as the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and the Ankylosing Spondylitis Disease Activity Score-C-Reactive Protein (ASDAS-CRP), highlighting its potential for routine clinical application (11).