Key clinical point: Ankylosing spondylitis and axial psoriatic arthritis may be two distinctly different diseases.
Major finding: At baseline, ankylosing spondylitis patients with and without psoriasis, compared with axial psoriatic arthritis patients, had more back pain (90% and 92% vs. 21%; P less than .001) and worse back metrology (Bath Ankylosing Spondylitis Metrology Index of 3.1 and 2.3 vs. 1.9; P less than .001), and at follow-up had worse axial disease activity scores on the Bath Ankylosing Spondylitis Disease Activity Index (4.1 and 3.9 vs. 3.5; P = .02).
Study details: A retrospective analysis of four groups from two observational longitudinal cohorts: ankylosing spondylitis patients with and without psoriasis, along with axial and peripheral psoriatic arthritis patients.
Disclosures: The University of Toronto Psoriatic Arthritis Program is supported by a grant from the Krembil Foundation, but this study received no specific funding to carry out the research. Dr. Feld reported being supported by a grant from Novartis. The authors reported no conflicts of interest.
Feld J et al. Rheumatology. 2019 Oct 8. doi: 10.1093/rheumatology/kez457.