The HOPE 4 trial (Heart Outcomes Prevention and Evaluation 4) investigated the effectiveness of a comprehensive, collaborative model of care, implemented in Colombia and Malaysia, which aimed to reduce cardiovascular disease risk in individuals with hypertension. One component of this intervention was the nomination of a treatment supporter, where participants could select a family member or friend to assist them with their care. The purpose of this study was to investigate the impact of these individuals on participant outcomes, as well as the relationship dynamics between participants and their treatment supporter.