Protocol: Implementation evaluation of a combination intervention for sustainable blood pressure control in rural KwaZulu-Natal, South Africa (IMPACT BP): A three-arm, unblinded, parallel group individually randomized clinical trial

Background: Hypertension is the primary risk factor for stroke and heart disease, which are leading causes of death in South Africa. Despite the availability of treatments, there is an implementation gap in how best to deliver hypertension care in this resource-limited region.

Methods: We describe a three-arm parallel group individually randomized control trial to evaluate the effectiveness and implementation of a technology-supported, community-based intervention to improve blood pressure control among people with hypertension in rural KwaZulu-Natal. The study will compare three strategies: 1) standard of care (SOC arm) clinic-based management, 2) home-based blood pressure management supported by community blood pressure monitors (CBPM arm) and a mobile health application to record blood pressure readings and enable clinic-based nurses to remotely manage care, and 3) an identical strategy to the CBPM arm, except that participants will use a cellular blood pressure cuff, which automatically transmits completed readings over cellular networks directly to clinic-based nurses (eCBPM+ arm). The primary effectiveness outcome is change in blood pressure from enrollment to 6 months. The secondary effectiveness outcome is the proportion of participants with blood pressure control at 6 months. Acceptability, fidelity, sustainability, and cost-effectiveness of the interventions will also be assessed.

Conclusions: In this protocol, we report the development of interventions in partnership with the South Africa Department of Health, a description of the technology-enhanced interventions, and details of the study design so that our intervention and evaluation can inform similar efforts in rural, resource-limited settings.