Researchers Identify Differences Between Axial Psoriatic Arthritis and Ankylosing Spondylitis

Persons with ankylosing spondylitis (AS)—with or without psoriasis—have different demographic, genetic, radiographic, and clinical variables from persons with axial psoriatic arthritis (axPsA), according to results of a new study. The findings suggest that axPsA is a distinct entity.

The researchers compared data of patients with AS with psoriasis (n=91) and patients with AS without psoriasis (n=675) with data of patients with axPsA (n=477) and patients with peripheral PsA (n=826).

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All patients’ cases were followed prospectively using the same protocol. A logistic regression analysis was performed and adjusted for follow-up duration.

Results showed that patients with AS with or without psoriasis were younger, were more often male, were positive for HLA-B*27 antigen, had received more treatment with biologics, and had a higher grade of sacroiliitis.

Additionally, patients with AS had more back pain at presentation, worse Bath Ankylosing Spondylitis Disease Activity Index and Bath Ankylosing Spondylitis Metrology Index scores, and worse physician global assessments.

Similar differences were detected when patients with AS and psoriasis were compared with those with axPsA, and in a regression model.

—Melinda Stevens

Reference:

Feld J, Ye JY, Chandran V, et al. Is axial psoriatic arthritis distinct from ankylosing spondylitis with and without concomitant psoriasis? [published online October 8, 2019]. Rheumatology. doi:10.1093/rheumatology/kez457.