To describe the design and methodology of APACHE, a cohort of patients with early peripheral psoriatic arthritis (pPsA), and to assess the main baseline clinical characteristics of the first included patients.

APACHE is an ongoing prospective multicentre national cohort ( NCT03768271 ) with a planned follow-up of 10 years. Included patients have recent-onset ( < 12 months) peripheral arthritis, a personal and/or family history of psoriasis, pPsA diagnosed by a rheumatologist, and no history of targeted disease-modifying antirheumatic drug therapy. At inclusion, demographic data, disease activity, comorbidities, and imaging results (not reported here) are collected. A descriptive analysis of these data was performed.

The first 186 study patients had a mean age of 44 ± 11 years and mean arthritis duration of 6 ± 4 months; 84 (45%) were women; 169 (91%) had a history of psoriasis (mean duration, 14 years) and 71 (38%) were receiving methotrexate. Disease activity was moderate with a mean DAPSA score of 19 ± 14 and mean swollen and tender joint counts of 2.1 ± 3.2 and 6.0 ± 8.0, respectively. The initially involved joints were mainly the hands (40%) and knees (28%). Entheseal pain (39%) was more prevalent than dactylitis (27%). Comorbidities were common, with obesity in 27% and at least one cardiovascular risk factor or disease in 49% of patients.

Patients with early peripheral PsA had moderate disease activity, a predominant oligoarticular profile, and a high prevalence of entheseal pain.