Clinical and radiological changes during psoriatic arthritis disease progression.

Objective: To determine the contribution of radiological findings at the initial visit with respect to classifying patients with psoriatic arthritis (PsA); and to determine the extent to which the clinical disease patterns change over time.

Methods: Patients with PsA were followed prospectively at 6-12 month intervals since 1978; 86 patients were registered within 1 year of diagnosis and were followed for at least 1 year. Based on the clinical information, including the actively inflamed joint count, damaged joint count, and the presence of back disease and arthritis mutilans, a clinical PsA pattern was assigned. A separate radiology pattern based on radiographs alone, and a combined clinical and radiological pattern, was also assigned at each visit. The initial clinical pattern was compared to the initial combined clinical-radiological pattern, and the initial clinical pattern was compared to the clinical pattern at 1 year and 5 years in 35 patients with both 1 and 5 year followup.

Results: In 23% of the patients, the radiological assessment in the initial visit showed evidence of patterns not detected clinically; 49% and 77% of the patients showed clinical pattern change within 1 year and 5 years, respectively. A comparison between the group that changed pattern and the one that did not change pattern in 5 years revealed no significant features.

Conclusion: Radiological assessments add information not gained from clinical assessment alone. Clinical patterns do change over time in the majority of patients. Both elements must be taken into consideration when developing classification criteria for PsA.