Outcome Measures in Psoriatic Arthritis.
In the last decade, there have been significant advances in outcome measure research in psoriatic arthritis (PsA). In this article, the outcome measures for disease activity in individual key domains of PsA are reviewed, followed by the key patient-reported outcome measures of function, quality of life, fatigue, and a new measure for disease impact, the psoriatic arthritis impact of disease. New research into composite measures of psoriatic disease is summarized, including response measures and proposed cutoff points for disease activity. Finally, the key future issues in outcome measurement in PsA are addressed.