Radiographic progression in ankylosing spondylitis/axial spondyloarthritis

Abstract

Radiographic progression in the axial skeleton is considered as an important outcome in ankylosing spondylitis (AS) and in the whole group of axial spondyloarthritis (SpA). Recently new data on the rates and predictors of radiographic progression from observational cohorts have become available. Here we summarize recent data and discuss their clinical relevance and directions for further investigations. Nonradiographic axial SpA progresses to AS with a rate of about 12% over 2 years; elevated C-reactive protein (CRP) is an important predictor of such a progression. The rate of radiographic progression in the spine is strongly dependent on the presence of the following risk factors: syndesmophytes at baseline, elevated acute phase reactants (CRP and/or erythrocyte sedimentation rate) and smoking. The presence of radiographic damage in the spine has a strong impact on spinal mobility and functional status, although the association of radiographic sacroiliitis progression with the functional status remains unclear. Radiographic progression in the spine and, to a lesser extent, in the sacroiliac joint represents a clinically relevant clinical outcome and treatment target in AS/axial SpA.