Pharmacy cost sharing, antiplatelet therapy utilization, and health outcomes for patients with acute coronary syndrome.

OBJECTIVES

To examine how cost sharing for prescription drugs affects compliance with antiplatelet therapy and subsequent health outcomes among patients with acute coronary syndrome (ACS).

STUDY DESIGN

Retrospective outcomes study using administrative data from medical and pharmaceutical claims of patients enrolled at health plans offered by 26 large employers drawn from all regions of the country.

METHODS

A total of 14,325 patients were diagnosed as having ACS and underwent coronary stent implantation between 2002 and 2005. Each patient was followed up for a maximum of 2 years. Primary outcomes measures were adoption of outpatient antiplatelet therapy, adherence to outpatient therapy, hospital admissions, and healthcare expenditures.

RESULTS

Patients with ACS who face higher coinsurance are less likely to adopt outpatient antiplatelet therapy within the first month after stent implantation and are more likely to discontinue treatment in the first year after stent implantation (P <.01). Higher coinsurance is also associated with an increased number of ACS rehospitalizations (P <.01). For patients in health plans with higher coinsurance rates, expected costs from ACS hospitalizations are $2796 (38%) higher in the first year after stent implantation (P <.01).

CONCLUSIONS

Higher copayments for prescription drugs are associated with lower utilization of antiplatelet therapy and with higher likelihood of rehospitalization among patients with ACS. As a consequence, total healthcare spending for patients with ACS increases by approximately $615 in the first year after stent implantation.