Adherence to antiplatelet therapy for one year following myocardial infarction (MI) was improved when the cost of the co-payment was waived, according to results from the ARTEMIS trial presented by Tracy Wang, MD, FACC, in a Late-Breaking Clinical Trial session on Sunday, March 11 at ACC.18 in Orlando, FL.

The first large, prospective, multicenter trial to examine how co-payment vouchers affect patient adherence to recommended medical therapy enrolled 11,001 patients who had been treated for MI at one of 301 U.S. hospitals. All patients had health insurance – 64 percent had private insurance, while 42 percent had Medicare and 9 percent had Medicaid. Among all patients, 17 percent reported they previously had not filled a prescription because it was too expensive.

In a cluster design, participating hospitals were randomly assigned to either the intervention arm (131 hospitals) or usual-care arm (136 hospitals). A total of 6,436 patients were in the intervention arm (and received a voucher) and 4,565 patients were in the usual-care arm. Patients were enrolled prior to hospital discharge and physicians used their clinical judgment to prescribe clopidogrel or ticagrelor.

The study's co-primary endpoint for adherence was continued use of the prescribed antiplatelet drug at one year without a gap in use of 30 days or longer.

More patients in the intervention arm than the usual care arm reported taking their medication as prescribed (87 vs. 84 percent). Greater adherence with the voucher was confirmed with a validation analysis using pharmacy records in 8,360 patients (55 percent vs. 46 percent with usual care). An adherence rate of 92 percent was found with the voucher compared with 88 percent in the usual-care group among 944 patients who had periodic checks of medication blood levels. Further, more patients received ticagrelor rather than clopidogrel in the intervention arm (59.6% vs. 32.4%). However, this strategy did not impact clinical outcomes: for the co-primary endpoint of the composite of MI, stroke or death from any cause, there was no difference between groups.

Wang noted the study had insufficient statistical power to identify a difference between groups for the co-primary endpoint, as 28 percent of patients who received vouchers did not use them. “We used vouchers to reduce co-payments because our patients were covered by multiple types of insurance and used a wide range of pharmacies and pharmacy benefit management services to obtain their medications,” she said. “But vouchers only provide the intended co-payment reduction if a patient chooses to or remembers to use it. Patients who never used the provided voucher had the highest rates of non-persistence and adverse clinical outcomes.” 

Ultimately, co-payment reduction improved medication prescription and use, Wang said. However, Wang noted that the findings raise further questions about how to deploy co-payment reduction strategies to improve clinical outcomes and patient adherence. Further analysis of the data is planned.

Keywords: ACC18, ACC Annual Scientific Session, Angina, Stable, Purinergic P2Y Receptor Antagonists, Myocardial Infarction, Health Expenditures, Medicaid, Ticlopidine, Adenosine, Myocardial Infarction, Stroke, Treatment Outcome, Diabetes Mellitus, Percutaneous Coronary Intervention, Insurance, Health, Medicare

< Back to Listings