TOPLINE:

Syndesmophytes developed in nearly 1 in 5 patients with psoriatic arthritis (PsA) during long-term observation, with the incidence declining in recent decades. Higher erythrocyte sedimentation rate (ESR) and radiographic sacroiliitis scores were independently associated with syndesmophyte development.

METHODOLOGY:

• Researchers analyzed data from 1584 patients with PsA from a prospective longitudinal cohort in Toronto, Ontario, Canada, enrolled between January 1978 and April 2025 to examine the associations between disease activity markers across multiple PsA domains and the development of spinal structural damage.
• Participants underwent comprehensive evaluations at 6- to 12-month intervals, with radiographs of the cervical and lumbar spine and sacroiliac joints obtained at baseline and biennially thereafter to assess structural damage.
• Peripheral joint radiographs were scored using the modified Steinbrocker method, sacroiliac joint involvement was assessed according to the modified New York criteria, and spinal structural damage was evaluated based on syndesmophyte presence through consensus reading by at least two experienced rheumatologists.
• The outcome was the development of spinal structural damage, defined as the appearance of at least one new syndesmophyte.

TAKEAWAY:

• During a median follow-up of 8.5 years, 18.0% of patients without syndesmophytes at baseline developed new syndesmophytes (median time to development, 5.8 years). Among patients without axial disease at baseline, 30.1% experienced progression to axial disease.
• Compared with the risk for syndesmophyte development in the reference period of 1978-1988, the risks progressively declined over subsequent years (hazard ratio [HR], 0.26; 95% CI, 0.17-0.40 for 2000-2010 and HR, 0.16; 95% CI, 0.08-0.33 for 2011-2025).
• Elevated ESR (adjusted HR, 1.02; 95% CI, 1.01-1.03) and higher radiographic sacroiliitis scores (adjusted HR, 1.19; 95% CI, 1.07-1.32) were independently associated with syndesmophyte development.

IN PRACTICE:

“[The study] findings help define a clinical profile that drives axial disease progression,” the authors of the study wrote.

SOURCE:

The study was led by Fadi Kharouf, MD, Centre for Prognosis Studies in the Rheumatic Diseases, Schroeder Arthritis Institute, University Health Network, Toronto. It was published online on April 15, 2026, in Rheumatology.

LIMITATIONS:

The single-center observational design may limit the generalizability of findings. Radiographic assessments were performed through consensus reading, rather than through independent blinded evaluations. The lack of advanced imaging modalities may have led to underdetection of important features such as enthesitis and nonradiographic sacroiliitis, which could influence the effect estimates.

DISCLOSURES:

The Gladman Krembil Psoriatic Arthritis Research Program received funding from the Krembil Foundation and the Schroeder Arthritis Institute. One author reported support from the Dr Dafna D. Gladman Chair in Psoriatic Arthritis Research at University Health Network, and another author reported receiving support from a grant provided by the Krembil Foundation. Two authors reported receiving grants and consulting/speaker fees or honoraria from pharmaceutical companies. One author reported being a member of the board of directors of the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis and is its co-vice president; he also mentioned his spouse’s employment with AstraZeneca.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.