CRP and spondylitis: Concomitant fibromyalgia and other pain syndromes as well as osteoarthritis and structural damage may coexist in patients with D2M axSpA and may partly explain the persistence of signs and/or symptoms suggestive of active disease.27 This is because pain perception is heavily weighted in indices of disease activity of axSpA.28 For example, the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), is entirely reliant on patient-reported outcomes (PROs), while the ASDAS, is primarily driven by PROs, and both do not require signs of objective inflammatory activity, apart from CRP in ASDAS.