The Counseling Older Adults to Control Hypertension (COACH) trial: design and methodology of a group-based lifestyle intervention for hypertensive minority older adults

Abstract

The disproportionately high prevalence of hypertension and its associated mortality and morbidity in minority older adults is a major public health concern in the United States. Despite compelling evidence supporting the beneficial effects of therapeutic lifestyle changes on blood pressure reduction, these approaches remain largely untested among minority elders in community-based settings. The Counseling Older Adults to Control Hypertension trial is a two-arm randomized controlled trial of 250 African-American and Latino seniors, 60 years and older with uncontrolled hypertension, who attend senior centers. The goal of the trial is to evaluate the effect of a therapeutic lifestyle intervention delivered via group classes and individual motivational interviewing sessions versus health education, on blood pressure reduction. The primary outcome is change in systolic and diastolic blood pressure from baseline to 12 months. The secondary outcomes are blood pressure control at 12 months; changes in levels of physical activity; body mass index; and number of daily servings of fruits and vegetables from baseline to 12 months. The intervention group will receive 12 weekly group classes followed by individual motivational interviewing sessions. The health education group will receive an individual counseling session on healthy lifestyle changes and standard hypertension education materials. Findings from this study will provide needed information on the effectiveness of lifestyle interventions delivered in senior centers. Such information is crucial in order to develop implementation strategies for translation of evidence-based lifestyle interventions to senior centers, where many minority elders spend their time, making the centers a salient point of dissemination.

Trial registration: ClinicalTrials.gov NCT01180673.

Copyright © 2013. Published by Elsevier Inc.

Figures

Figure 1

Conceptual model of the effects of Motivational Interviewing and its mediators

Figure 2

COACH study design

Figure 3

Panel A shows the original power calculations incorporating heterogeneous variances and BP correlations over time. (s=standard deviation). Panel B shows the revised power calculations using ANCOVA: SBP average point reduction over one year (sample size, m per group, power=0.80, r=observed average correlation over time):

Figure 4

Revised power calculations with observed data for DBP using an ANCOVA model: Sample size m per group (power=0.80).