Sequential Multiple Assignment Randomized Trial to Reduce Food Insecurity

Overview

Food insecurity affects 20% of the 116 million people in the US with hypertension and is associated with poor adherence to evidence-based treatments and disparities in hypertension outcomes. Interventions are being used to address food insecurity in clinical care settings, but people differ in the support they need to reduce food insecurity and little is known about which food insecurity interventions work best, or for whom. The goal of this study is to develop and test an adaptive food insecurity intervention using a Sequential Multiple Assignment Randomized Trial to determine which initial food insecurity intervention is more effective in improving adherence and blood pressure in patients with hypertension and for those who do not respond to the initial intervention, evaluate how to best provide additional support.

In the US, 47% of adults have hypertension (HTN), and HTN is the leading cause of cardiovascular disease morbidity and mortality. Uncontrolled HTN increases the risk of cardiovascular disease, chronic kidney disease, and cognitive impairment. Current guidelines recommend the adoption of a healthy diet as an integral part of ongoing treatment regardless of the underlying antihypertensive drug treatment. The Dietary Approaches to Stop Hypertension (DASH) eating pattern is a diet rich in fruits, vegetables, and whole grains with a reduced content of sodium and saturated fat. The DASH is the diet with the strongest evidence to be effective for lowering blood pressure. Despite the evidence base for the effectiveness of DASH as well as pharmacological treatments, economic factors are common barriers to individuals with HTN adhering to treatments. Adherence is multidimensional and involves initiation, implementation, and persistence. Food insecurity (FI), the lack of consistent access to the food needed for a healthy life, is an important factor that leads to HTN disparities. Individuals living in food insecure households are less likely to adhere to prescribed HTN treatments, such as DASH and medications, and more likely to have worse blood pressure control. Because of the prevalence of FI and associated poor health outcomes, a growing number of health systems and health insurers are investing in integrating interventions to address FI as part of routine clinical care. These interventions include 1) providing information to patients about community resources), 2) utilizing community health workers (CHW), and 3) home delivery of medically tailored meals (MTM). Studies have shown these FI interventions have varying levels of success on improving food security and health. However, people often need varying levels of support to address needs, and, rather than using only one single intervention to address FI, there remains a gap in understanding whether adaptively allocating resources based on need has the potential to more effectively, equitably, and efficiently improve food security and health for a greater proportion of patients. To advance the science in patient adherence and blood pressure management, this study will conduct a sequential multiple assignment randomized trial (SMART) among food-insecure patients with uncontrolled HTN. SMART uses experimental design principles to determine whether and how to alter treatments to build optimal adaptive interventions. This study will assess the change in adherence and blood pressure over time (0-9 months). This study will also evaluate if treatment options were more effective for particular patients. Several other measures are included in this study to learn more about how an adaptive intervention designed to address FI affects blood pressure, adherence, food security, health-related quality of life, and other key risk factors for blood pressure control in patients with HTN. The proposed Sequential Multiple Assignment Randomized Trial to reduce Food Insecurity and Improve Adherence in Patients with Hypertension (SMART-FI) is a single-site, open-label, longitudinal two-stage SMART. Participants will be randomized to one of two first-stage treatments for 3 months: 1) information about community resources or 2) in-person CHW support. Participants who do not have a 10mmHg improvement in systolic blood pressure (SBP) at 3 months will be re-randomized to one of two second-stage treatments for an additional 3 months: 1) CHW support or 2) home delivery of MTM. The study will recruit 224 participants for this trial. Participants will engage in the interventions up to 6 months and will be followed for a total of 9 months. In Aim 1, the study will determine which first-stage FI intervention is more effective in improving adherence and blood pressure. In Aim 2, the study will evaluate which FI intervention is the best next step for those who do not respond to the initial intervention. In Aim 3, the study will explore how, why, and under what circumstances participants achieved improvements to the first- and second-stage interventions by conducting semi-structured interviews with participants and evaluating for potential predictors of heterogeneity in response to each intervention.