Objectives The purpose of this study was to compare radiographic outcomes according to the magnitude of the response utilizing 2 new psoriatic composite disease activity measures (the Psoriatic Arthritis Disease Activity Score (PASDAS),and the GRAPPA Composite Exercise (GRACE))  with DAS28 as a comparator. The data were taken from the GO-REVEAL dataset, a large (N=324) randomised, double-blind, study which evaluated the safety and efficacy of 2 doses of golimumab in subjects with active PsA.
Methods Data collected in the GO-REVEAL study was not sufficient to calculate all the components of the GRACE index, soimputation was used to obtain values for the PsA quality of life measure (PsAQoL). Response criteria at 24 weeks were applied across the whole dataset, irrespective of treatment group. Radiographic scores at baseline and 24 weeks were assessed.
Results Radiographic progression was greater in subjects with a poor outcome with treatment, and less in those with a good outcome. Radiographic scores were intermediate for those with a moderate outcome (Table). Analysis of variance statistics were significant for all three measures but were more significant for the psoriatic arthritis specific indices. Data were also generated for the proportion of subjects in whom no radiographic progression was seen, and these data were compared across the outcome measures using chi-squared statistics: PASDAS, 82% in good outcome group did not have radiographic progression χ2 =8.5, GRACE 80%, χ2 =6.6, DAS28, 76% χ2 =4.6.
Conclusions Response criteria for disease specific composite measures enable better separation between groups in terms of radiographic progression and may therefore be used as suitable targets for interventional studies and in the clinic.
Helliwell PS, Fitzgerald O, Fransen J: Composite Disease Activity and Responder Indices for Psoriatic Arthritis: Development of Cut-offs for Both Disease Activity States and Response. J Rheum, in press (2014).
Disclosure of Interest P. Helliwell Consultant for: Janssen, A. Kavanaugh Grant/research support: Janssen