Identification and characteristics of patients with axial psoriatic arthritis: clinical, phenotypic, and imaging associations
Konstantinos D Vassilakis, Charalampos Papagoras, Sousana Gazi, Evangelia Mole, Michael Krikelis, Paraskevi V Voulgari, Evripidis Kaltsonoudis, Nikolaos Koletsos, Pelagia Katsimpri, Dimitrios Boumpas, Dimitrios Katsifis-Nezis, Nikolaos Kougkas, Maria Boutel, Theodoros Dimitroulas, Petros P Sfikakis, Maria G Tektonidou, Artemis Galani, Nikolaos Michalakeas, Dimitrios P Bogdanos, Theodora Simopoulou, Christos Koutsianas, Evgenia Mavrea, Gkikas Katsifis, Konstantinos Kottas, Maria Konsta, Evangelia Kataxaki, Eleni Kalavri, Kalliopi Klavdianou, Charalampos Sfontouris, Dimitrios Daoussis, George Iliopoulos, Ilias Bournazos, Dimitrios Karokis, Constantinos Georganas, Dimos Patrikos, Dimitrios Vassilopoulos, George E FragoulisAbstract
Objective
To present the clinical and imaging characteristics of patients with Axial Psoriatic Arthritis (PsA) and to identify possible subtypes.
Methods
Data were retrieved from the Greek-multicentre PsA study. Axial PsA (axPsA) was defined as PsA (CASPAR criteria) accompanied by inflammatory back pain (present or ever) and positive imaging findings of the sacroiliac joints and/or spine (MRI: active inflammation of sacroiliac joints and/or spine; X-rays: 1984 New York-criteria for radiographic sacroiliitis and/or presence of syndesmophytes in the spine). Demographic and clinical characteristics were compared between axPsA and non-axPsA subsets. Two additional analyses were conducted: a. Isolated sacroiliac joint involvement (sacroiliac axPsA) vs isolated involvement of the rest of the spine (spinal axPsA). b. non-radiographic axPsA (nr-axPsA, positive MRI findings only) vs radiographic axPsA (r-axPsA, positive X-ray findings).
Results
Among 922 patients with PsA, 238 (25.8%) had axPsA. Patients with axPsA had less frequently peripheral arthritis at diagnosis, whereas had increased rates of HLA-B27 positivity, enthesitis ever and inflammatory bowel disease. Among patients with axPsA, 42% (n = 101) had isolated sacroiliac axPsA and 32% (n = 75) had isolated spinal axPsA. Sacroiliac axPsA was associated with younger age (OR: 0.97, 95% CI: 0.94–0.99) and enthesitis at diagnosis (OR: 3.37, 95% CI: 1.66–6.82). 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.
Conclusion
Approximately one quarter of patients with PsA exhibit axial involvement, and among them, ∼30% have isolated spinal axPsA and nr-axSpA, respectively.