Progression in psoriatic arthritis: Role of time varying clinical indicators

Objective, We have shown that the presence of 5 or more effusions and high medication use at first clinic visit predicted clinical progression in pati ents with psoriatic arthritis (PsA), while a low erythrocyte sedimentation rate (ESR) was "protective." These clinical indicators will change over the course of a patient's disease. We investigated whether there is additional prognostic information available through monitoring these indicators at ea ch clinic visit. Methods. A total of 365 patients with at least 2 followup visits at the PsA Clinic who did not have 10 or more damaged joints at first visit were incl uded. Clinical assessments including the number of actively inflamed and da maged joints were carried out every 6-12 mo according to a standard protoco l. The analysis used a generalized linear model that relates the number of damaged joints that developed between consecutive clinic visits to the info rmation available at the first of the 2 visits, and in which the informatio n was added to a baseline model including the first visit variables previou sly shown to be important. Results. Single factor analysis suggested that the addition of functional c lass, number of actively inflamed joints, and Lansbury index provide progno stic information for subsequent damage. The final multivariate model includ es time varying information on the number of actively inflamed joints, func tional class, and current damage, as well as first visit information on pri or medication as predictive of progression of damage, plus male sex and a l ow ESR at first visit as "protective," Conclusion. Time varying predictors for damage are important and should be monitored longitudinally in patients with PsA.