Predictors for radiological damage in psoriatic arthritis: results from a single centre

Background: The predictors for the development of clinical damage in psoriatic arthritis (PsA) have been reported previously. Aim: To identify predictors for radiological damage in PsA. Methods: Patients followed-up prospectively according to a standard protocol at The University of Toronto between 1978 and 2004 were included. The principal outcome was the change in the number of damaged joints between visits, both clinically and radiologically. Explanatory variables considered included: sex, age, duration of arthritis at first visit, time in clinic, number of tender swollen joints, functional class, erythrocyte sedimentation rate (ESR), concentration of drugs and, to adjust for within-patient correlation, the number of clinically damaged joints at the first of the two visits over which change was observed. Results: At the time of this analysis, 625 patients were recorded in the database. Multivariate analyses of predictors for both clinical and radiological damage show that age, time in clinic, initial ESR, number of tender and swollen joints at previous visit, and number of deformed joints at previous visit were related to both clinical and radiological damage. Conclusions: The number of actively inflamed joints, particularly the number of swollen joints, was associated with the progression of radiological damage. The higher the number of previously damaged joints, the higher the risk for progression of damage. Thus, patients with PsA need to be treated, even in the presence of damage as long as there is evidence of inflammation, to prevent the progression of damage.