Use and misuse of ezetimibe: analysis of use and cost in Saskatchewan, a Canadian jurisdiction with broad access.

Background: Saskatchewan is the only Canadian province that lists ezetimibe for open formulary access even though it is a second-line agent for lowering cholesterol.

Methods: A retrospective analysis of ezetimibe use in Saskatchewan between 2002 and 2011 was carried out using provincial health administrative databases. Overall use and costs of ezetimibe were described over time. Among new users of ezetimibe, the percentage who received the drug as first-line monotherapy was estimated. First-line monotherapy was defined as no statin dispensations in the 365 days before and the 60 days after the first ezetimibe dispensation. Potential predictors of first-line monotherapy were assessed using generalized linear mixed-effect models.

Results: In 2004, ezetimibe represented 2.5% of cholesterol-lowering dispensations. In 2011, its use increased to 8.8% of cholesterol-lowering dispensations and 13.2% of the total cost of cholesterol-lowering agents. Overall, ezetimibe was used as first-line monotherapy in 23% of all new users (4024 of 17,475 patients). Approximately half of all cases of first-line monotherapy were prescribed by 10.4% (112 of 1074) of prescribers in the cohort. Patients who had experienced previous acute coronary syndrome or who had undergone coronary revascularization procedures were significantly less likely to receive first-line monotherapy.

Conclusions: A high proportion of ezetimibe's use is not in accordance with evidence-based recommendations. Suboptimal prescribing could partially explain current patterns of use; however, other factors such as medication nonadherence may have played an important role. Restricting ezetimibe use in the provincial formulary in addition to improving prescribers' awareness through academic detailing should be considered.