Rationale and design of the IMProving Adherence to medications for breast Cancer and cardiovascular disease equiTably (IMPACT) randomized clinical trial

Background: Cardiovascular disease (CVD) is a leading cause of mortality in patients with early-stage breast cancer (BC), many of whom are prescribed endocrine therapy (ET) to prevent BC recurrence. Yet, nonadherence to ET and CVD medications is common among BC survivors, particularly in underserved populations at high risk for adverse outcomes. Little is known about how to equitably improve medication adherence for multiple chronic conditions. Methods: The IMProving Adherence to Medications for Breast Cancer and Cardiovascular Disease EquiTably (IMPACT) trial is an investigator-initiated, single-center (multisite), two-arm randomized trial. Patients in BC clinics are screened for nonadherence to ET and CVD medications (antihypertensive or statin) using prescription fill data and a self-report questionnaire. A total of 300 patients with stage I-III BC who screen positive for nonadherence will be randomized to receive an equity-focused multicomponent medication adherence intervention versus minimally-enhanced usual care. The intervention includes nurse-led medication reconciliation, a one-time optional training in the use of the electronic patient portal and a smartphone adherence-focused application, and two structured pharmacist counseling sessions tailored to patients' adherence barriers. The control group receives medication reconciliation only. The primary outcome is adherence to ET and CVD medications by self-report and pharmacy fill data at 28 weeks. Key secondary outcomes include medication adherence at 52 weeks, adherence to individual medication classes, CVD risk factor control (BP, LDL), and patient-reported outcomes. Discussion: The IMPACT trial will determine the effect of a multicomponent medication adherence intervention that targets nonadherent patients and is tailored to individual-level reasons for nonadherence. Trial registration: ClinicalTrials.gov (NCT 05496829).