An RCT of the effect of motivational interviewing on medication adherence in hypertensive African Americans: Rationale and design

Background: Hypertension disproportionately affects African Americans compared to whites, and it is the single most common explanation for the disparity in mortality between African Americans and whites. Adherence with antihypertensive medications can help reduce risk of negative hypertension-related outcomes. Motivational interviewing is a promising patient-centered approach for improving adherence in patients with chronic diseases. In this paper we describe the rationale and design of an ongoing randomized controlled trial testing the effectiveness of motivational interviewing versus usual care in improving medication adherence among 190 African American uncontrolled hypertensive patients, who receive care in a primary care setting. Methods: The usual care group receives standard medical care, while those in the intervention group receive standard care plus four sessions of motivational interviewing at 3-month intervals for a period of 1 year. This technique consists of brief, patient-driven counseling sessions to facilitate initiation and maintenance of behavior change. The primary outcome is adherence to prescribed antihypertensive medication, assessed with the electronic medication events monitoring system (MEMS) and the Morisky self-report adherence questionnaire. Secondary outcomes are within-patient changes in blood pressure, self-efficacy, and intrinsic motivation between baseline and 12 months. We report the baseline sociodemographic and clinical characteristics of the participants. Conclusions: Despite the potential utility of motivational interviewing, little is known about its effectiveness in improving medication adherence among hypertensive patients, especially African Americans. In addition to the baseline data this study has generated, this trial should provide data with which we can assess the effectiveness of this approach as a behavioral intervention.