Axial Spondyloarthritis Diagnostic Tools Work for Men and Women Alike

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Dutch researchers found that both women and men with potential axial spondyloarthritis (axSpA) benefit from HLA-B27 typing and imaging modalities for diagnosis.

Gender and axSpA
Axial spondyloarthritis can be subdivided into radiographic axSpA (r-axSpA) and non-radiographic axSpA, which is a precursor to sacroiliac joint (SIJ) structural damage. Men are more likely to suffer from r-axSpA than women.

Conflicting data exist on gender differences related to the presentation and severity of axSpA. Ortolan and colleagues¹ in the Netherlands sought to analyze gender differences at the time of diagnosis of axSpA. They looked at variations in early disease presentation in an effort to determine whether different diagnostic approaches are needed based on gender.

The study
The researchers used a large inception cohort of patients with chronic back pain (The SPondyloArthritis Caught Early cohort). Subjects had back pain of greater than 3 months’ and less than 2 years’ duration. All participants had a full diagnostic work-up, including family history, symptoms, presence of other inflammatory diseases, drug treatments, smoking history, HLA-B27 typing, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) level, and plain radiographs of the spine and magnetic resonance imaging (MRI) scans of the SIJ. Ultimately, 719 patients were included in the analysis.

Next: the results and take-home points for clinicians

The results
• Of the 275 male patients with chronic back pain, 146 (53%) received a certain diagnosis of axSpA, and of the 444 female patients with chronic back pain, 155 (35%) received a certain diagnosis of axSpA.

• Male patients with chronic back pain were significantly more likely to receive a diagnosis of axSpA.

• Male patients were younger than female patients at the time of diagnosis of axSpA.

• Men were significantly more often HLA-B27-positive (80% vs 60%; P < .001) and more often had imaging abnormalities (any positive imaging: 78% vs 64%; P = .007) compared with women.

• The total number of spondyloarthritis features without HLA-B27 and imaging results was not different between men and women.

• After multivariate regression, HLA-B27 positivity, elevated CRP level and/or ESR, and positive MRI scans of sacroiliac joints were independently associated with the diagnosis of axSpA in men.

• In the female population with chronic back pain, HLA-B27 positivity and positive MRI scans and plain radiographs of the sacroiliac joints were independently associated with the diagnosis of axSpA.

• Male gender and HLA-B27 positivity were independently and positively associated with imaging positivity.

• Disease activity scores were higher in female subjects, while functional indices were not different between men and women.

Take-home points
• While chronic back pain may be prevalent in women, men are two times more likely to receive a diagnosis of axSpA.

• Be suspicious of axSpA in young men who present with chronic back pain.

• HLA-B27 screening and imaging remain useful tools in both men and women with suspected axSpA.

• Clinicians should not expect the same male gender predominance in axSpA as found in r-axSpA.

• There are differences in early axSpA presenting characteristics (eg, imaging abnormalities occur earlier in men); however, there is no reason to alter the initial diagnostic approach between men and women.

References:

1. Ortolan A, van Lunteren M, Ramiro S, et al. Are gender-specific approaches needed in diagnosing early axial spondyloarthritis? Data from the SPondyloArthritis Caught Early cohort.Arthritis Res Ther. 2018;20:218. doi: 10.1186/s13075-018-1705-x.