Arthritis Hit Rate in Patients with Psoriasis Referred for Rheumatology Evaluation

Abstract

Background: Psoriatic arthritis (PsA) is a chronic inflammatory arthritis that occurs in a large proportion of patients with psoriasis causing pain and impaired quality of life. Early recognition and treatment are important as PsA may result in structural joint damage with a risk of reduced physical function.

Objectives: The aim of this study was to determine the proportion of psoriasis patients with suspicion of PsA who are diagnosed with PsA or other rheumatologic conditions following referral from a dermatology department. Furthermore, the study aimed to identify clinical and patient-reported variables identifying patients with psoriasis in whom joint discomfort is an expression of PsA.

Methods: This single-center retrospective study included all patients with psoriasis who had been referred for rheumatological evaluation on suspicion of PsA in the period from 2014 to 2018.

Results: A total of 364 patient records were reviewed. This identified 106 patients with psoriasis who had been referred for rheumatologic evaluation on suspicion of PsA. Patients with a previous diagnosis of PsA were excluded from the analysis. Among the referred patients, 23.6% were diagnosed with either peripheral or axial PsA or both. A total of 23.6% were diagnosed with osteoarthritis and an additional 14.2% were diagnosed with inactive PsA. For patient-reported swollen joints and dermatologist-assessed swollen joints at referral, the positive predictive values/negative predictive values for a PsA diagnosis were 40%/100% and 50%/92%, respectively.

Conclusion: In this study, 23.6% of patients with psoriasis symptoms suggestive of PsA were diagnosed with axial and/or peripheral arthritis following rheumatologic evaluation. Patient-reported swollen joints and dermatologist-assessed swollen joints indicated a high likelihood of peripheral PsA. Additionally, the absence of patient-reported swollen joints indicated a very low probability of establishing a diagnosis of peripheral PsA.

Keywords: Psoriasis; Psoriatic arthritis; Screening.