A Novel Just-in-Time Contextual Mobile App Intervention to Reduce Sodium Intake in Hypertension: Protocol and Rationale for a Randomized Controlled Trial (LowSalt4Life Trial)

Background High sodium intake is a significant public health problem in the United States. Interventions that lower sodium intake can decrease blood pressure and improve cardiovascular outcomes. Restaurants and grocery stores are prime targets for intervention with about 77% of all sodium intake in the average US diet coming from processed and restaurant foods. Objective This study proposes that a mobile app intervention that promotes low-sodium alternatives at grocery stores and restaurants will reduce dietary intake of sodium and improve confidence following a low-sodium diet in hypertension. Methods In this single-center, prospective, open-label study, patients will be randomized to a mobile app or usual care for 8 weeks. We will randomize 50 patients (age>18 years) diagnosed with hypertension and on antihypertensive therapy for at least 3 months in a 1:1 manner stratified by gender. Study subjects will receive the mobile app, LowSalt4Life, or usual dietary advice for 8 weeks. LowSalt4Life provides a multifaceted intervention based on just-in-time contextual tailored messages at grocery stores and restaurants. The primary endpoint is the change in the estimated 24-hour urinary excretion of sodium from spot urine. Secondary outcomes include change in the sodium content of the food frequency questionnaire, confidence in following a low-sodium diet, urine chloride and creatinine dipsticks, and blood pressure. Results The project was funded in May 2016 until April 2018. This trial is currently enrolling patients. To date, 26 of the 50 patients needed have been enrolled. Results will be available in the Spring of 2019. Conclusions This randomized controlled trial will test the efficacy of just-in-time contextual tailored messages through a novel mobile app 8-week intervention on urinary sodium excretion in patients with hypertension. We will address a critical evidence gap in the care of patients with hypertension. If effective, this intervention could be scaled to assess effects on blood pressure and cardiovascular events in hypertension. Trial Registration ClinicalTrials.gov NCT03099343; https://clinicaltrials.gov/ct2/show/NCT03099343 (Archived by WebCite at http://www.webcitation.org/735HNzKlQ) International Registered Report Identifier (IRRID) PRR1-10.2196/11282


DESCRIPTION (provided by applicant):
High dietary sodium intake is linked to incident hypertension, stroke, heart failure and kidney disease. U.S. federal guidelines advocate daily sodium intake of less than 2,300 milligrams (mg) with further reduction to 1,500 mg in persons who are 51 and older and those of any age who are African American and/or have hypertension, diabetes, or chronic kidney disease. The estimated average sodium intake for Americans is 3,400 mg per day. In recent years, consumption of pre-processed and restaurant foods has substantially increased, and more than 75% of sodium in the average U.S. diet now comes from these sources. Most patients prescribed a low sodium diet either do not understand or possess the information about sodium content of the foods they eat and current IT approaches to reduce sodium intake focus solely on counting the amount of dietary sodium eaten. We will develop a mobile application that incorporates geofencing technology and provides just-in-time mobile push messages at the 2 main locations hypertensive patients interact with processed and prepared foods, at a grocery store or eating at a restaurant. Geofencing technology allows the mobile application to be aware of the user's location and provide location-specific messages, vital for the just-in-time nature of the intervention. The proposed project will establish a geofencing based adaptive notification message system for the mobile application using participant feedback to facilitate reducing dietary sodium intake and will then determine the effectiveness of the mobile application in helping hypertensive patients reduce dietary sodium intake and feel more confident in following a low sodium diet. These data will be crucial for a planned randomized clinical trial to test the sustained effects of the mobile application on blood pressure and sodium intake. The application of this technological approach has positive implications in improving self-management and reducing disease morbidity.

PUBLIC HEALTH RELEVANCE:
High dietary sodium intake is linked to high blood pressure, stroke, heart failure and kidney disease. U.S. federal guidelines advocate daily sodium intake of less than 2,300 milligrams (mg). The estimated average sodium intake for Americans is 3,400 mg per day. In recent years, consumption of pre-processed and restaurant foods has substantially increased, and more than 75% of sodium in the average U.S. diet now comes from these sources. We plan to develop and test the effectiveness of a mobile application to help hypertensive patients reduce the amount of dietary sodium intake using mobile push notifications at grocery stores and restaurants.

CRITIQUE NOTE:
The sections that follow are the essentially unedited, verbatim comments of the individual committee members assigned to review this application. The attached commentaries may not necessarily reflect the position of the reviewers at the close of group discussion, nor the final majority opinion of the group. The above RESUME/SUMMARY OF DISCUSSION represents the evaluation of the application by the entire committee.

CRITIQUE 1
Significance: 1 Investigator(s): 2 Innovation: 2 Approach: 1 Environment: 1 Overall Impact: Strengths This application proposes a study that addresses an important problem -excessive salt intake in patients with hypertension. It is using an innovative method (customized telephone messaging) that has been shown to be effective in other areas of medicine. This method is also completely automated and thus promises to be cost effective -an important consideration at the time when healthcare costs are rising. The proposal is well thought through and clearly written.

Weaknesses
No weaknesses noted.

Significance: Strengths
Addresses an important medical problem -excessive salt intake in patients with hypertension. The health IT method proposed in the application holds significant promise -if successful, it could be used in a cost-effective fashion on a wide scale -a critical consideration for a condition as common as hypertension.

Weaknesses
No weaknesses noted.

Investigators: Strengths
The Principal Investigator is a new PI to NIH. However, he has already held several other funding awards and has a number of publications to his name. Finally, thoughtfulness and clarify of the proposal itself inspire confidence in his ability to execute the study.

Weaknesses
No weaknesses noted.

Innovation: Strengths
Telephone messaging is an innovative strategy that has already been shown to be successful in several medical realms. Its success is highly dependent on the content [of the messages] as well as on form [messages] through which this content is delivered. The investigators have clearly given a great deal of thought on how to make this content user-friendly and have high potential to succeed. Geofencing is another innovative health IT approach being used in this proposal. It allows for automation and customization of the messages directed to the patient, and may be the key to their success.

Weaknesses
No weaknesses noted.

Approach: Strengths
The investigators' Research Plan carefully lays out the steps they will take to accomplish their Specific Aims. They start with hypotheses; conduct focus groups to develop these hypotheses further guided by patient feedback; and finally implement the resulting product and test its effectiveness. These are exactly the steps one needs to take when developing and evaluating a new IT technology. Outcomes being measured are appropriate. Proposed statistical analysis and power calculations are appropriate.

Weaknesses
A single-blind (outcome analysis) design should be considered -there is nothing to prevent blinding the individual who will assess the outcomes to the intervention vs. control assignments. It could be of interest to evaluate on blood pressure as an exploratory outcome. But of course in a small trial of 4 weeks duration impact on blood pressure is less likely to be noticeable.

Environment: Strengths
The environment includes everything needed for success of the project: general research infrastructure (library, etc.), stimulating environment (multiple other investigators), strong technical / IT infrastructure available at the Center for Health Communications Research, as well as colleagues with the expertise needed for this project.

Weaknesses
No weaknesses noted.

Protection of Human Subjects from Research Risks:
Acceptable.

Inclusion of Women and Minority Subjects: Acceptable.
Inclusion of AHRQ Priority Populations: Acceptable.

Degree of Responsiveness: Acceptable.
Budget and Period of Support: Acceptable.

CRITIQUE 2
Significance: 4 Investigator(s): 3 Innovation: 5 Approach: 5 Environment: 2 Overall Impact: Strengths Reducing sodium intake by making individual aware of their food choices and providing alternate options based in their location can make an impact on individual's choices. The concept of proactively trying to impact individual's food choices instead of having the application be purely reactive can make an impact in how useful the tool is to users.

Weaknesses
One of the challenges in IT evaluation is ensuring that the users utilize the application. The proposal does not identify mechanisms for ensuring that users utilize the application during the trial or if they are not utilizing finding out why (i.e. a technical issue, a training issue, etc.).
There is little discussion about the usability of the application. It would be hard to assess the usefulness of the application without addressing the usability of it.

Significance: Strengths
Identifying mechanisms to lower high sodium intake levels through the use of mobile applications is significant. The use of geofencing as a mechanism to identify where an individual is in order to help identify the types of food that may be lower in sodium content can make a significant impact.

Weaknesses
The use of a randomized control trial without addressing usability issue could negatively impact the results.
The system design process is not clear. Is this a user-centered design process? Are users only involved in the design process at the beginning?

Investigators: Strengths
The research team has a solid background in the problem space.

Weaknesses
The research team should consider bringing on a usability/Human-Computer Interactions expert to oversee the design/evaluation of the system.

Innovation: Strengths
The use of geofencing to provide food recommendations is potentially innovative.

Weaknesses
The design/data collection process is not innovative. The use traffic light labels for sodium levels are not innovative.

Approach: Strengths
The use of traffic light labels as a way to address literacy concerns is strength.
The use of theory of planned behavior to guide the behavior change approach is a strength.

Weaknesses
Little discussion of the design process or how users would be involved in the process. Little discussion about addressing usability issues. The focus of the application seems to be on the messaging and does not really attempt to address the technology challenges.

Environment: Strengths
There seems to be strong organizational support for the project.

Weaknesses
No weaknesses noted.