Back pain is very common in the community, and therefore an evidence-based referral strategy is valuable to guide GPs in referring patients with inflammatory back pain when axial spondyloarthritis is suspected.
Ankylosing spondylitis (AS) is the recognisable name that has been used to describe inflammatory arthritis of the spine and sacroiliac joints (SIJs) for decades, although the naming of this group of conditions has evolved. To be classified as having AS a patient has to have erosive damage in their SIJs detected on plain radiograph; however, we know that the inflammatory arthritis starts long before erosions are detected in the SIJs with plain radiographs. Patients who present earlier can have inflammation detected on MRI that has not caused erosions in the SIJs. This condition in these patients has now been given the name nonradiographic axial spondyloarthritis (nr-axSpA).1 Therefore, to bring together these two concepts, the umbrella term ‘axial spondyloarthritis’ (axSpA) has been introduced. AxSpA encompasses both nr-axSpA (which can be considered an early form of AS) and AS.