The changing face of axial spondyloarthritis over the last 25 years

Axial spondyloarthritis has undergone major changes since the turn of the century, concerning terminology (from ankylosing spondylitis to radiographic axial spondyloarthritis), classification criteria, introduction of targeted therapies (anti-TNF, anti-IL17, JAK inhibitors), and management strategies. Epidemiological data indicate an increasing incidence and a shorter diagnostic delay. Over the past 25 years, additional modifications have been observed: recognition of non-radiographic forms (up to 50 % in recent studies), lower male predominance with a sex ratio tending to parity, reduced frequency of HLA-B27 and uveitis, wider use of targeted treatments, and changes in treatment response profiles. Overall disease severity appears to be reduced according to several indicators, including mortality, hip involvement, structural progression, and amyloidosis. The determinants of these changes remain debated and discussed in this narrative review, in the absence of long-term longitudinal studies and because of limited comparability across different time periods. The impact of environmental factors still needs to be assessed.