Spondyloarthritis features can identify axial spondyloarthritis

(HealthDay)—For patients with chronic back pain, the presence of at least one of three spondyloarthritis (SpA) features can identify possible axial spondyloarthritis (axSpA), according to a study published online Jan. 27 in Arthritis & Rheumatology.

Atul Deodhar, M.D., from the Oregon Health & Science University in Portland, and colleagues enrolled 751 U.S. patients in a study to identify the proportion with axSpA among those with chronic back pain and one or more of three SpA features. Participants had to have chronic back pain for three months or longer, starting before age 45 years, and have one or more of the following: positive human leukocyte antigen B27, current inflammatory back pain, and magnetic resonance imaging/X-ray evidence of sacroiliitis. None of the patients had a prior SpA diagnosis.

The researchers found that 46 percent of the 697 patients with available data were given a clinical diagnosis of axSpA by the investigator. Overall, 47 percent of 744 participants met the Assessment of SpondyloArthritis international Society (ASAS) criteria for axSpA. Of these, 238 were classified as non-radiographic axSpA, and 108 had ankylosing spondylitis; two of the patients had missing data. Specificity and sensitivity of the ASAS criteria were 79 and 81 percent, respectively, using the investigator's clinical diagnosis as gold standard.

"Among patients with chronic back pain for ≥3 months beginning at age <45 years, the presence of ≥1 of 3 SpA features is an effective way to identify patients with possible axSpA," the authors write.

Several authors disclosed financial ties to pharmaceutical companies, including AbbVie, which funded the study.