Axial Involvement Affects a Quarter of Psoriatic Arthritis Patients, With Distinct Clinical and Imaging Profiles
Roughly one-quarter of patients with psoriatic arthritis (PsA) show evidence of axial involvement, according to a study published in Rheumatology. This large Greek multicenter study also identified distinct subtypes based on clinical presentation and imaging characteristics.
In the study, among 922 patients with PsA, 238 (25.8%) had axPsA. It examined both sacroiliac and spinal involvement using X-ray and MRI criteria. Axial PsA (axPsA) was defined as inflammatory back pain with positive imaging findings—either radiographic sacroiliitis or active spinal inflammation.
Patients with axPsA were less likely to have peripheral arthritis at diagnosis but had higher rates of HLA-B27 positivity, enthesitis, and inflammatory bowel disease, suggesting a different disease phenotype than their non-axial counterparts.
A deeper look into the axPsA subset revealed further heterogeneity. “Among patients with axPsA, 42% (n = 101) had isolated sacroiliac axPsA and 32% (n = 75) had isolated spinal axPsA,” the authors noted. Sacroiliac disease was more likely in younger patients (OR: 0.97; 95% CI: 0.94–0.99) and those with enthesitis at diagnosis (OR: 3.37; 95% CI: 1.66–6.82).
The study also distinguished between radiographic and non-radiographic axPsA. “A total of 35% of patients with axPsA had nr-axPsA and were more commonly females (OR: 2.59, 95% CI: 1.39–4.82) and younger (OR: 0.96, 95% CI: 0.94–0.99) compared with those with r-axPsA,” researchers found.
“Approximately one-quarter of patients with PsA exhibit axial involvement, and among them, ∼30% have isolated spinal axPsA and nr-axPsA, respectively,” concluded the study authors.
Reference
Vassilakis KD, Papagoras C, Gazi S, Mole E, et al. Identification and characteristics of patients with axial psoriatic arthritis: clinical, phenotypic and imaging associations. Rheumatology (Oxford). 2025 Aug 1;64(8):4539-4545. doi: 10.1093/rheumatology/keaf137. PMID: 40059325.
