Axial Spondyloarthritis More Common than Previously Thought

Researchers writing in the July 2016 issue of Arthritis and Rheumatology show that axial spondyloarthritis (SpA) is more common among patients being treated for chronic back pain than previously thought.

Of 697 patients enrolled in this multi-center, non-drug treatment, single visit study conducted at rheumatology practices in the U.S., 319 (46%) were diagnosed as having axial SpA and 348 of 744 (47%) fulfilled the ASAS criteria - of whom 238 were classified as having nonradiographic axial SpA and 108 as having ankylosing spondylitis (AS).

The study, called the Prevalence of Axial SpA (PROSpA) study, was conducted to determine the proportion of patients with nonradiographic axial SpA among those with chronic back pain for at least three months. The patients were 45 years old or younger and were identified with at least one of the following diagnosis criteria:  HLA–B27 positivity, current inflammatory back pain, and imaging (magnetic resonance imaging [MRI] or radiographic) evidence of sacroiliitis.  [[{"type":"media","view_mode":"media_crop","fid":"49865","attributes":{"alt":"©Mirana/Shutterstock.com","class":"media-image media-image-right","id":"media_crop_9876619203526","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"6062","media_crop_rotate":"0","media_crop_scale_h":"0","media_crop_scale_w":"0","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"font-size: 13.008px; line-height: 1.538em; float: right;","title":"©Mirana/Shutterstock.com","typeof":"foaf:Image"}}]]

“Overall, these findings emphasize the need to improve the identification and diagnosis of both AS and nonradiographic axial SpA among patients already receiving care in rheumatology practices and those newly referred to rheumatologists,” wrote the researchers who were led by Atul Deodhar, M.D., of Oregon Health & Science University in Portland.

“Increased disease awareness and the use of appropriate referral criteria can reduce the delay to diagnosis and provide a better understanding of the prevalence of axial SpA. These patients experience a similar burden of disease and their disease can remain undiagnosed and, therefore untreated, for many years,” the authors wrote.

Both ankylosing spondylitis (AS) and nonradiographic axial spondyloarthritis (SpA) typically go undiagnosed for years. Although AS and nonradiographic axial SpA have comparable clinical manifestations, AS is more easily identified by the presence of sacroiliitis on radiographs.

Nonradiographic axial SpA may affect as many women as men, whereas AS more often affects men.

“The delay to diagnosis of axial SpA can be partly attributed to delayed referral to rheumatologists,” the authors wrote.

Disclosures:

The study was funded by AbbVie

References:

"Frequency of Axial Spondyloarthritis Diagnosis AmongPatients Seen by US Rheumatologists for Evaluation of Chronic Back Pain." Arthritis & Rheumatology.  Vol. 68, No. 7, July 2016, pp 1669–1676DOI 10.1002/art.39612