Difference in Medication Adherence Between Patients Prescribed a 30-Day Versus 90-Day Supply After Acute Myocardial Infarction

Abstract

Background Evidence-based medication adherence rates after a myocardial infarction are low. We hypothesized that 90-day prescriptions are underused and may lead to higher evidence-based medication adherence compared with 30-day fills. Methods and Results We examined patients with myocardial infarction treated with percutaneous coronary intervention between 2011 and 2015 in the National Cardiovascular Data Registry. Linking to Symphony Health pharmacy data, we described the prevalence of patients filling 30-day versus 90-day prescriptions of statins, β-blockers, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, and P2Y₁₂ inhibitors after discharge. We compared 12-month medication adherence rates by evidence-based medication class and prescription days' supply and rates of medication switches and dosing changes. Among 353 259 patients with myocardial infarction treated with percutaneous coronary intervention, 90-day evidence-based medication fill rates were low: 13.0% (statins), 12.3% (β-blockers), 14.6% (angiotensin-converting enzyme inhibitors/angiotensin receptor blockers), and 9.7% (P2Y₁₂ inhibitors). Patients filling 90-day prescriptions were more likely older (median 69 versus 62 years) with a history of prior myocardial infarction (25.0% versus 17.9%) or percutaneous coronary intervention (30.3% versus 19.5%; P<0.01 for all) than patients filling 30-day prescriptions. The 12-month adherence rates were higher for patients who filled 90-day versus 30-day supplies: statins, 83.1% versus 75.3%; β-blockers, 72.7% versus 62.9%; angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, 71.1% versus 60.9%; and P2Y₁₂ inhibitors, 78.5% versus 66.6% (P<0.01 for all). Medication switches and dosing changes within 12 months were infrequent for patients filling 30-day prescriptions-14.7% and 0.3% for 30-day P2Y₁₂ inhibitor fills versus 6.3% and 0.2% for 90-day fills, respectively. Conclusions Patients who filled 90-day prescriptions had higher adherence and infrequent medication changes within 1 year after discharge. Ninety-day prescription strategies should be encouraged to improve post-myocardial infarction medication adherence.

Keywords: adherence; evidence‐based medications; myocardial infarction.

Figure 1. Adherence by evidence‐based medication class and prescription days' supply at 12 months.

ACEi indicates angiotensin‐converting enzyme inhibitors; and ARBs, angiotensin receptor blockers.

Figure 2. Illustration of months during which medication switches or dosing changes occurred among patients prescribed a 90‐day fill.

A, Month the medication switch occurred among patients prescribed a 90‐day fill. B, Month the dosing change occurred among patients prescribed a 90‐day fill. ACEi indicates angiotensin‐converting enzyme inhibitors; and ARBs, angiotensin receptor blockers.