Can we identify axial spondyloarthritis among young adults referred to non-rheumatology specialists? Results from the SHERPAS study

Objective

To determine the prevalence and features associated with axSpA diagnosis in young adults with chronic back pain (CBP) referred to specialists other than rheumatologists, and to evaluate magnetic resonance imaging (MRI) of sacroiliac joints (SIJ) in this population.

Methods

A prospective, observational study was conducted from July 2021 to October 2023. Adults aged 18–40 years with CBP referred for spinal MRI by non-rheumatology specialists were included. Participants completed a self-administered questionnaire assessing back pain characteristics and SpA features. The spinal MRI was extended to SIJ. Thereafter, participants were evaluated by a rheumatologist, who established the diagnosis of axSpA based on clinical evaluation and complementary tests.

Results

Among 268 patients enrolled, 8 (3.0 %) were diagnosed with definite axSpA, and 14 (5.2 %) suspected axSpA cases, resulting in a total of 8.2 % with definite or suspected axSpA. Buttock pain (54.5 % vs. 24.3 %; p = 0.04), improvement with NSAIDs (68.2 % vs. 36.5 %; p = 0.02), shorter symptom duration (3.5 vs. 5.1 years; p = 0.02), HLA-B27 positivity (27.3 % vs. 3.3 %; p < 0.01), and elevated CRP levels (36.4 % vs. 12.2 %; p = 0.01) were associated with axSpA diagnosis. MRI findings revealed spinal degenerative lesions in most patients, and SIJ abnormalities in almost one third, being more common in patients with axSpA.

Conclusion

In our cohort of young adults with CBP referred to non-rheumatology specialists, approximately 8 % were diagnosed with definite or suspected axSpA. MRI spinal lesions were reported in most patients, while SIJ findings were reported in one out of three patients.