Axial psoriatic arthritis: update on a longterm prospective study.

OBJECTIVE

To evaluate changes in symptoms, spinal mobility, and radiographic features in patients with axial psoriatic arthritis (AxPsA).

METHODS

Patients with AxPsA were identified from the University of Toronto Psoriatic Arthritis clinic database. Axial symptoms, metrology, and radiographic features at study entry were compared to 5-year and 10-year followup assessments. Data were analyzed using continuity adjusted McNemar's test, an exact binomial test, or logistic regression.

RESULTS

Of 297 patients (mean age 42.5 yrs, PsA duration 8 yrs) in the study, 56% had axial symptoms, 43% had radiographic evidence of sacroiliitis, and 13% had syndesmophytes at entry. The number of patients with neck/back pain, neck/back stiffness, and clinical sacroiliitis declined significantly at both 5- and 10-year followup periods. There was a significant increase in the number of patients with restricted cervical spinal mobility at both 5- and 10-year visits and significant reduction in lateral flexion at both timepoints. At 5 (10) years, of those without sacroiliitis at baseline, 36.6% (51.7%) developed at least grade 2 sacroiliitis; 46.5% (52.0%) of those who presented with grade 2 progressed to a higher grade; and 15.6% (25.0%) with grade 3 progressed to grade 4 sacroiliitis. Of the patients without cervical/thoracic/lumbar syndesmophytes at study entry, 11%/16%/14% (14%/21%/20%) developed syndesmophytes in these regions at 5 (10) year followup. Similar results were obtained when analyses were restricted to patients satisfying radiographic criteria alone.

CONCLUSION

Over a 10-year period, patients with AxPsA had improvement in neck and back pain, but lateral spinal flexion and cervical mobility deteriorated.