Disease characteristics in patients with and without psoriatic arthritis treated with etanercept

Background: Patients with psoriasis (PsO) and psoriatic arthritis (PsA) have functional disability, pain and emotional problems, and experience lower quality of life (QoL) than patients with PsO alone.

Objectives: Examine effectiveness of etanercept (ETN) in patients with PsO alone, and with PsA, and determine whether PsA patients on ETN experience rapid QoL improvement.

Methods: Data from three phase III trials using ETN in adults with moderate-to-severe PsO were pooled. Patients with (n = 523) and without (n = 1330) PsA received ETN 25 mg once weekly to 50 mg twice weekly or placebo for 12-24 weeks. Assessments included Psoriasis Area and Severity Index (PASI), Dermatology Life Quality Index (DLQI), EuroQoL-5D (EQ-5D), Study 36-item Short Form Health Survey (SF-36) and Hamilton Depression Rating Scale (HAM-D).

Results: Baseline PASI, EQ-5D and SF-36 physical component summary scores were worse for PsA patients. With ETN, PASI for PsA and non-PsA groups improved as early as week 2. Scores for both groups converged by week 12. EQ-5D and SF-36 physical component improved faster in PsA patients, with EQ-5D scores converged by week 2. For total DLQI and most components, both groups had similar baseline scores and improved over 24 weeks on ETN. While the PsA group had more depressed patients at baseline, after 24 weeks on ETN it showed a greater reduction in the number of depressed patients than the non-PsA group.

Conclusions: In patients with PsO involving ≥10% of body surface area, skin disease and QoL are worse in PsA patients. With ETN, QoL improved rapidly in PsA patients.