Length of Initial Prescription at Hospital Discharge and Long-Term Medication Adherence for Elderly, Post-Myocardial Infarction Patients: Protocol for an Interrupted Time Series Study

Abstract

Background: Based on high-quality evidence, guidelines recommend the long-term use of secondary prevention medications post-myocardial infarction (MI) to avoid recurrent cardiovascular events and death. Unfortunately, discontinuation of recommended medications post-MI is common. Observational evidence suggests that prescriptions covering a longer duration at discharge from hospital are associated with greater long-term medication adherence. The following is a proposal for the first interventional study to evaluate the impact of longer prescription duration at discharge post-MI on long-term medication adherence.

Objective: The overarching goal of this study is to reduce morbidity and mortality among post-MI patients through improved long-term cardiac medication adherence. The specific objectives include the following. First, we will assess whether long-term cardiac medication adherence improves among elderly, post-MI patients following the implementation of (1) standardized discharge prescription forms with 90-day prescriptions and 3 repeats for recommended cardiac medication classes, in combination with education and (2) education alone compared to (3) usual care. Second, we will assess the cost implications of prolonged initial discharge prescriptions compared with usual care. Third, we will compare clinical outcomes between longer (>60 days) versus shorter prescription durations. Fourth, we will collect baseline information to inform a multicenter interventional study.

Methods: We will conduct a quasiexperimental, interrupted time series design to evaluate the impact of a multifaceted intervention to implement longer duration prescriptions versus usual care on long-term cardiac medication adherence among post-MI patients. Intervention groups and their corresponding settings include: (1) intervention group 1: 1 cardiac center and 1 noncardiac hospital allocated to receive standardized discharge prescription forms supporting the dispensation of 90 days' worth of cardiac medications with 3 repeats, coupled with education; (2) intervention group 2: 4 sites (including 1 cardiac center) allocated to receive education only; and (3) control group: all remaining hospitals within the province that did not receive an intervention (ie, usual care). Administrative databases will be used to measure all outcomes. Adherence to 4 classes of cardiac medications - statins, beta blockers, angiotensin system inhibitors, and secondary antiplatelets (ie, prasugrel, clopidogrel, or ticagrelor) - will be assessed.

Results: Enrollment began in September 2017, and results are expected to be analyzed in late 2020.

Conclusions: The results have the potential to redefine best practices regarding discharge prescribing policies for patients post-MI. A policy of standardized maximum-duration prescriptions at the time of discharge post-MI is a simple intervention that has the potential to significantly improve long-term medication adherence, thus decreasing cardiac morbidity and mortality. If effective, this low-cost intervention to implement longer duration prescriptions post-MI could be easily scaled.

Trial registration: ClinicalTrials.gov NCT03257579; https://ichgcp.net/clinical-trials-registry/NCT03257579.

International registered report identifier (irrid): DERR1-10.2196/18981.

Keywords: adherence; cardiology; discharge; elderly; heart; intervention; medication; policy change; post-myocardial infarction; prescription; prevention; secondary prevention; standardized discharge prescription form.

Conflict of interest statement

Conflicts of Interest: None declared.

©J D Schwalm, Noah M Ivers, Zachary Bouck, Monica Taljaard, Madhu K Natarajan, Lisa Dolovich, Kednapa Thavorn, Tara McCready, Erin O'Brien, Jeremy M Grimshaw. Originally published in JMIR Research Protocols (http://www.researchprotocols.org), 04.11.2020.

Figures

Figure 1

Persistence with secondary prevention medications after angiography. ACE: angiotensin-converting enzyme.

Figure 2

Intervention and control groups in the Myocardial Infarction Prescription Adherence Duration (MIPAD) study.

Figure 3

Example discharge prescription from Hamilton Health Sciences with intervention revisions circled.

Figure 4

Flow of participants into the study during the pre-intervention period (preliminary data used for power calculation). Notes: Patient age determined at procedure date – 120 days. CAD: coronary artery disease; CCN-CR: Cardiac Care Network – Cardiac Registry; CIHI-DAD: Canadian Institute for Health Information - discharge abstract database; MI: myocardial infarction; RPDB: registered persons database.