The burden of psoriatic arthritis in the biologics era: data from the Belgian Epidemiological Psoriatic Arthritis Study.

Objectives: To characterize the frequency of PsA subtypes, estimate the severity based on damage and inflammation and estimate the impact of PsA on patients' health-related quality of life.

Methods: We conducted a longitudinal observational study in 17 academic and non-academic centres in Belgium. Patients with PsA fulfilling Classification Criteria for Psoriatic Arthritis were recruited. Three visits were scheduled: at baseline (T0), at 1 year (±1 month; T1) and at 2 years (±1 month; T2) of follow-up. Demographics, clinical data and patient-reported outcome measures were collected at T0, T1 and T2. X-rays of the hands and feet were collected yearly (T0, T1 and T2). X-rays of the spine were collected at T0 and T2. Here we report on the burden of disease based on the clinical data and patient-reported outcomes.

Results: A total of 461 patients were recruited; 73.5% had combined peripheral and axial involvement and 13.7% had hip involvement. Plaque psoriasis was predominant (83.9%). At inclusion, 42.7% and 58.8% had no tender or swollen joints, respectively. Dactylitis and enthesitis were still present in 13.7% and 24.1% of the patients, respectively. Patients was treated with DMARDs (68%) and/or anti-TNF (44.2%). Forty-three per cent of the patients had a state of minimal disease activity and 62% considered the actual state as satisfactory. The mean HAQ score was 0.7%, with 32.5% of patients having a normal score (<0.3).

Conclusion: Despite the availability of different treatment options, including biologics (anti-TNF), a substantial number of patients have active disease and have a high disease burden.