Clinical outcomes in psoriatic arthritis: A systematic literature review

Many outcomes have been proposed in the assessment of psoriatic arthritis (PsA). The Outcome Measures in Rheumatology (OMERACT) core set for PsA evaluation comprises 6 domains: joints, skin, function, pain, patient's global assessment, and quality of life. The objective of this work was to assess reporting of outcomes in PsA, including patient-reported outcomes (PROs) in recent publications.

A systematic literature search of clinical trials related to PsA and reporting at least 1 clinical outcome between 2006 and 2010 was performed in PubMed, i.e., just before to just after publication of the OMERACT core set. All clinical outcomes were noted and subdivided into domains of health. Data analysis was descriptive.

Fifty-eight articles (12,405 patients) were included in the analysis: 17 (29%) were randomized clinical trials; the patients' mean ± SD age was 48.2 ± 5.4 years and the mean ± SD disease duration was 9.0 ± 3.1 years. Eighty-four different outcomes were reported, with a mean ± SD of 6.9 ± 4.3 per study. Patients were mainly assessed using the 6 core set domains, reported in 37.9% (quality of life) to 55.2% (skin) of articles; however, the core set was rarely completely reported since only 10.3% of the studies reported all 6 core domains. PROs were heterogeneous and in particular there was no consensus regarding the number of joints to assess and instruments for dactylitis and enthesitis. PROs were assessed in more than 75% of publications using 28 different instruments.

There is great heterogeneity in PsA assessment, even since publication of the OMERACT core set. Better consensus on instruments to assess each domain of health and better insight into which outcomes are important for patients is needed.