Lessons learned from clinical phenotypes in early psoriatic arthritis: the real-world Dutch south west Early Psoriatic ARthritis study.

Objective: This paper describes the baseline demographics, clinical characteristics, and patient-reported outcomes (PROs) according to clinical phenotype of patients with early psoriatic arthritis (PsA) for the purpose of creating a decision support system for daily clinical practice. Method: Patients with newly diagnosed PsA were included in the Dutch south west Early Psoriatic ARthritis (DEPAR) study. No classification criteria were applied, to ensure collection of real-world data on demographics, medication, clinical characteristics, and PROs. An IT infrastructure facilitated data collection. Results: We described 527 patients, categorized according to the clinical phenotype stated by the rheumatologist at the time of diagnosis, namely monoarthritis (15%), oligoarthritis (40%), polyarthritis (23%), enthesitis (10%), axial disease (2%), and dactylitis (10%). Overall psoriasis severity was mild and 83 patients (16%) had no psoriasis. Short-term sick leave (> 1 day per 4 weeks) was 17% and long-term sick leave (> 4 weeks) was 4%. The group with phenotype enthesitis reported the longest duration of complaints, had the highest fatigue scores, and contained the highest percentage of patients with a Hospital Anxiety and Depression Scale (HADS) anxiety score ≥ 8 and depression score ≥ 8. Conclusion: PsA patients presenting at outpatient clinics in the Netherlands had a mild degree of psoriasis, with impairment of quality of life and work productivity. Most patients presented with phenotype oligoarthritis. Those presenting with phenotype enthesitis more often reported scores suggestive of an anxiety or depression disorder and fatigue. It is important for attending rheumatologists to be aware of these differences when assessing patients with PsA.