Health and imaging outcomes in axial spondyloarthritis

Abstract

This thesis focuses on the assessment and monitoring of health and imaging outcomes in axial spondyloarthritis (SpA) and the relationship between these outcomes. Four major contributions to the understanding and management of axial SpA were made: 1) the improvement and facilitation of the assessment of disease activity using the Ankylosing Spondylitis Disease Activity Score (ASDAS), for which we defined disease activity cut-offs and response criteria and provided guidance about the calculation of the score; 2) the increase in the knowledge about the mutual relationships between health outcomes in axial SpA, namely health related quality of life, physical function, clinical disease activity, spinal mobility, structural damage and magnetic resonance imaging (MRI) of the spine; 3) the increase in the knowledge about the factors that influence phenotypic variability in axial SpA, namely Human Leukocyte Antigen B27 (HLA-B27) positivity (a genetic factor), smoking (an environmental factor) and the presence of psoriasis (an extra-articular manifestation); and 4) the insight into the processes that drive structural progression in axial SpA and into the link between inflammation and structural damage, by specifically looking at the relationship between MRI inflammation, MRI fat deposition and new bone formation in axial SpA.