Composite Measures in Psoriatic Arthritis: a report from the GRAPPA 2009 annual meeting.

A composite measure is one way of incorporating an assessment of all relevant clinical outcomes into one single measure. By definition it incorporates several dimensions of disease status often by combining these different domains into a single score. Such instruments are well established in rheumatoid arthritis (RA), and these RA-specific measures have successfully been adopted for use in clinical trials involving patients with psoriatic arthritis (PsA). However, the need for a more PsA-specific composite measure has led to a number of proposals, which, for the large part, incorporate only peripheral articular disease activity. New indices that combine the diverse clinical manifestations of PsA are now under development. These issues were discussed at the 2009 annual meeting of GRAPPA (Group for Research and Assessment of Psoriasis and Psoriatic Arthritis) in Stockholm, Sweden, and are summarized here.