To examine 12-month retention rates over 6 years of etanercept patients in Canada, and to identify factors associated with treatment discontinuation. A retrospective cohort study was conducted using longitudinal prescription drug claims data from IQVIA Private Drug Plan database (PDP), Ontario Public Drug Plan database (OPDP), and Régie de l'assurance maladie du Québec database (RAMQ). Between 07/2008 and 06/2010, bio-naïve patients who initiated etanercept were identified and followed for 72 months. Twelve-month retention rates were estimated in one-year increments and factors associated with time to discontinuation over the 72-month period were identified using a Cox proportional hazards regression model. The study identified 4528 etanercept patients (61% female, 85% rheumatic diseases, and 15% psoriasis). Twelve-month etanercept retention rates increased significantly for patients following their first year on therapy (p < 0.0001), with 66% of patients retained at year 1 vs. 79, 82, 84, 83, and 79% at years 2, 3, 4, 5, and 6, respectively. 17.1% (n = 771) of patients were retained for the entire 72-month study. Patients with psoriasis were at increased risk (HR 1.199; p < 0.0001); while public drug coverage plan patients (OPDP HR 0.721; p < 0.0001 and RAMQ HR 0.537; p < 0.0001) were at decreased risk of treatment discontinuation. Twelve-month etanercept retention rates increased significantly for patients following their first year on therapy. Indication and drug coverage plan were associated with patients' time to etanercept discontinuation. With a better understanding of factors associated with retention, programs can be designed to address the specific needs of at-risk groups while supporting patients stable on therapy.
Keywords: Ankylosing spondylitis; Epidemiology; Psoriasis; Psoriatic arthritis; Rheumatoid arthritis.