Cardiovascular outcomes after a change in prescription policy for clopidogrel

Abstract

Background: Drug-reimbursement policies may have an adverse effect on patient outcomes if they interfere with timely access to efficacious medications for acute medical conditions. Clopidogrel in combination with aspirin is the recommended standard of care for patients receiving coronary stents to prevent thrombosis. We examined the population-level effect of a change by a Canadian provincial government in a pharmacy-benefits program from a prior-authorization policy to a less restrictive, limited-use policy on access to clopidogrel among patients undergoing percutaneous coronary intervention (PCI) with stenting after acute myocardial infarction.

Methods: We conducted a population-based, retrospective, time-series analysis from April 1, 2000, to March 31, 2005, of all patients 65 years of age or older with acute myocardial infarction who underwent PCI with stenting in Ontario, Canada. The primary outcome was the composite rate of death, recurrent acute myocardial infarction, PCI, and coronary-artery bypass grafting at 1 year, with adjustment for sex and age. The secondary outcome was major bleeding.

Results: The rate of clopidogrel use within 30 days after hospital discharge following myocardial infarction increased from 35% in the prior-authorization period to 88% in the limited-use period. The median time to the first dispensing of a clopidogrel prescription decreased from 9 days in the first period to 0 days in the second period. The 1-year composite cardiovascular outcome significantly decreased from 15% in the prior-authorization group to 11% in the limited-use group (P=0.02). Rates of bleeding in the two groups did not change.

Conclusions: The removal of a prior-authorization program led to improvement in timely access to clopidogrel for coronary stenting and improved cardiovascular outcomes.