Axial spondyloarthritis is a progressive form of arthritis which causes severe back pain because of inflammation of spinal and/or pelvic joints. If definite changes on plain radiographs are present, the disease is classified as ankylosing spondylitis (AS), but if they are absent the disease is classified as non-radiographic axial spondyloarthritis (nr-AxSpA). Usual therapy includes anti-inflamm…