Biologic therapy adherence, discontinuation, switching, and restarting among patients with psoriasis in the US Medicare population.

Background: Studies indicate adherence to biologics among patients with psoriasis is low, yet little is known about their use in the Medicare population.

Objective: We sought to investigate real-world utilization patterns in a national sample of Medicare beneficiaries with psoriasis initiating infliximab, etanercept, adalimumab, or ustekinumab.

Methods: We conducted a retrospective claims analysis using 2009 through 2012 100% Medicare Chronic Condition Data Warehouse Part A, B, and D files, with 12-month follow-up after index prescription. Descriptive and multivariate analyses were used to examine rates of and factors associated with biologic adherence, discontinuation, switching, and restarting.

Results: We examined 2707 patients initiating adalimumab (40.0%), etanercept (37.9%), infliximab (11.7%), and ustekinumab (10.3%); during 12-month follow-up, 38% were adherent and 46% discontinued treatment, with 8% switching to another biologic and 9% later restarting biologic treatment. Being female and being ineligible for low-income subsidies were associated with increased odds of decreased adherence. Outcomes varied by index biologic.

Limitations: Patient-reported reasons for nonadherence or gaps in treatment are unavailable in claims data.

Conclusion: Medicare patients initiating biologics for psoriasis had low adherence and high discontinuation rates. Further investigation into reasons for inconsistent utilization, including exploration of patient and provider decision-making and barriers to more consistent treatment, is needed.