Psoriasis treatment patterns with etanercept and adalimumab in a United States health plan population

Background: A retrospective study utilizing administrative claims from a US commercial health plan was performed to examine etanercept and adalimumab treatment patterns among patients with psoriasis (PSO). Methods: Biologic-naive PSO patients initiating etanercept or adalimumab therapy between 18 January 2008 and 31 December 2008 were identified. Patients continuously enrolled in the health plan for 6 months before and >= 12 months after therapy initiation were followed until disenrollment from the plan or 31 December 2009. Persistence was defined as continuous use of index TNF blocker without a gap in therapy >= 60 days. Patients with gaps in index therapy >= 60 days were classified as discontinuing, switching, or restarting the index therapy. Results: In total, 497 patients initiated etanercept and 330 the adalimumab therapy. Mean age for both groups was 43 years. Approximately 40-42% of patients were persistent on their index TNF blocker for 1 year. Among patients with a >= 60-day gap in therapy, discontinuation without restart or switch occurred in 37% of etanercept and 45% of adalimumab patients (p = 0.04). Differences in therapy restart or switching between the groups were not statistically significant. Conclusions: TNF-blocker therapy persistence is low among PSO patients in this health plan. More than one-third of patients restarted their index TNF blocker after a gap in therapy.