Copayment Reduction Voucher Utilization and Associations With Medication Persistence and Clinical Outcomes: Findings From the ARTEMIS Trial.

BACKGROUND

Cost is frequently cited as a barrier to optimal medication use, but the extent to which copayment assistance interventions are used when available, and their impact on evidence-based medication persistence and major adverse cardiovascular events is unknown.

METHODS AND RESULTS

The ARTEMIS trial (Affordability and Real-World Antiplatelet Treatment Effectiveness After Myocardial Infarction Study) randomized 301 hospitals to usual care versus the ability to provide patients with vouchers that offset copayment costs when filling P2Y inhibitors in the 1 year post-myocardial infarction. In the intervention group, we used multivariable logistic regression to identify patient and medication cost characteristics associated with voucher use. We then used this model to stratify both intervention and usual care patients by likelihood of voucher use, and examined the impact of the voucher intervention on 1-year P2Y inhibitor persistence (no gap in pharmacy supply >30 days) and major adverse cardiovascular events (all-cause death, myocardial infarction, or stroke). Among 10 102 enrolled patients, 6135 patients were treated at hospitals randomized to the copayment intervention. Of these, 1742 (28.4%) never used the voucher, although 1729 (99.2%) voucher never-users filled at least one P2Y inhibitor prescription in the 1 year post-myocardial infarction. Characteristics most associated with voucher use included: discharge on ticagrelor, planned 1-year course of P2Y inhibitor treatment, white race, commercial insurance, and higher out-of-pocket medication costs (c-statistic 0.74). Applying this propensity model to stratify all enrolled patients by likelihood of voucher use, the intervention improved medication persistence the most in patients with high likelihood of voucher use (adjusted interaction =0.03, odds ratio, 1.86 [95% CI, 1.48-2.33]). The intervention did not significantly reduce major adverse cardiovascular events in any voucher use likelihood group, although the odds ratio was lowest (0.86 [95% CI, 0.56-1.16]) among patients with high likelihood of voucher use (adjusted interaction =0.04).

CONCLUSIONS

Among patients discharged after myocardial infarction, those with higher copayments and greater out-of-pocket medication costs were more likely to use a copayment assistance voucher, but some classes of patients were less likely to use a copayment assistance voucher. Patients at low likelihood of voucher use benefitted least from copayment assistance, and other interventions may be needed to improve medication-taking behaviors and clinical outcomes in these patients. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02406677.