Compliance and Persistence with Concomitant Statin and Oral Antihyperglycemic Therapy

Objectives: To compare compliance and persistence with statin and oral antihyperglycemic therapies in patients with type 2 diabetes who received concomitant therapy.

Study Design: Retrospective cohort study using a large US commercial claims database.

Methods: Patients with type 2 diabetes and dispensed prescriptions for both statin and oral antihyperglycemic therapies on the same date in 2006 (index date = first date of such dispensing) were included in the analysis (N = 52,414). Patients were required to have continuous enrollment in the database for 1 year prior to (baseline) and 2 years after (follow-up) index date. The 2-year medication possession ratio (MPR) was compared between statin and oral antihyperglycemic therapy. For the persistence analysis, treatment discontinuation was defined by a gap >30 days between the last date of supply from previous dispensing and subsequent refill. The likelihood of discontinuation of statin versus oral antihyperglycemic therapy was estimated by fitting a robust Cox proportional hazards regression model, adjusted for baseline variables.

Results: The 2-year MPR was 70% for statin and 78% for oral antihyperglycemic therapy (P <.0001). The proportion of patients with a 2-year MPR >80% was 52% for statin and 63% for oral antihyperglycemic therapy (P <.0001). The median time to discontinuation of statin was significantly shorter compared with oral antihyperglycemic therapy (284 vs 495 days, P <.001). There was a greater risk to discontinue statin than oral antihyperglycemic therapy (adjusted hazard ratio: 1.47 [95% confidence interval 1.45-1.48]).

Conclusions: Compliance and persistence with statin therapy significantly lagged behind oral antihyperglycemic therapy in patients with type 2 diabetes who were treated concomitantly with both therapies.