Outcome measures in psoriatic arthritis: Where next?

OBJECTIVE: To provide an overview of commonly used outcome measure in psoriatic arthritis (PsA). BACKGROUND: PsA is a heterogenous inflammatory arthritis, associated with psoriasis that affects between 0.1% and 2% of the population and approximately one in three patients with psoriasis. Psoriatic arthritis places a significant burden on patients' overall quality of life and is associated with a range of comorbidities. Although assessment of patients and monitoring of symptoms has greatly improved over the last 2 decades, capturing disease activity in this multisystem disease remains challenging. Previous efforts have traditionally focussed on assessment of individual disease domains, however recent evidence suggests that composite measurements, particularly those incorporating patient reported outcomes may not only help monitor disease activity more accurately, but also help in accurately validating therapy outcomes in PsA patients. PURPOSE: This review discusses currently used outcome measurements in PsA and also highlights the importance of emerging measurements such as biomarkers and their possible role in capturing treatment response.