Work

A just-in-time adaptive mobile application intervention to reduce sodium intake and blood pressure in patients with hypertension: Rationale and design of the LowSalt4Life 2 trial

Year: 2025

Type: article

Abstract: BACKGROUND: Excess dietary sodium intake is a major contributor to hypertension (HTN) and cardiovascular disease in the U.S., yet most Americans exceed recommended sodium intake levels. Despite the established benefits of sodium reduction, behavioral adherence remains a challenge. Just-in-time adaptive interventions (JITAIs) provide a novel mobile health (mHealth) strategy to support low-sodium choices in real-time at restaurants and grocery stores. METHODS: LowSalt4Life 2 is a 6-month randomized controlled trial evaluating a mobile application-based sodium-focused JITAI among adults with HTN. In phase one, participants were randomized 1:1 to either the LowSalt4Life app with JITAI (App+JITAI) or the app alone. At 2 months, the App+JITAI group was re-randomized to either continue with the standard JITAI or receive a personalized JITAI (pJITAI) informed by reinforcement learning based on prior engagement. The primary outcome was change in systolic blood pressure (SBP) at 2 months. Secondary outcomes included changes in BP medication, dietary sodium intake, and engagement metrics. RESULTS: As of October 2025, 410 participants had been enrolled and completed follow-up. The trial's final results are anticipated in Spring 2025. Primary analysis focuses on the change in SBP between the App+JITAI and App-only groups, as well as the added value of personalization in the second study phase. CONCLUSIONS: LowSalt4Life 2 tests a scalable, context-aware digital intervention designed to reduce dietary sodium and improve BP management. By personalizing engagement based on user behavior, this study seeks to advance mHealth strategies for HTN self-management and inform future interventions targeting dietary behaviors in real-world settings.

Source: American Heart Journal

DOI: 10.1016/j.ahj.2025.107294