A Randomized Controlled Trial Evaluating a Novel Just-In-Time Contextual Mobile Application Intervention to Reduce Sodium Intake in Hypertension: The Lowsalt4life Trial

Introduction: Interventions that lower sodium intake can decrease blood pressure and improve cardiovascular outcomes. Methods: This single center, prospective, open-label study evaluated a new mobile app to reduce sodium intake. Patients > 18 years of age diagnosed with hypertension and on antihypertensive therapy for at least 3 months were enrolled. Participants were randomized 1:1, stratified by gender, to receive the mobile app, or usual dietary advice for 8 weeks. The app provides a multifaceted intervention based on just-in-time contextual tailored messages. The primary endpoint was the change in 24-hour urinary sodium excretion. Secondary outcomes included the change in estimated sodium intake from a Block Food Frequency Questionnaire (FFQ), 24-hr dietary recall, Self-care Confidence in Following a Low-Sodium Diet (SCFLSD) survey and blood pressure (BP). Results: Fifty patients (24 App, 26 No App) were randomized. Baseline demographics were similar between the groups. The average age was 57 years and BP 131/83 mmHg. The reduction in 24-hour urinary sodium excretion from baseline was greater in the App compared to No App group (p=0.30). The reduction in FFQ (p=0.008) and 24-hr dietary recall (p=0.11) sodium intake from baseline were greater in the App compared to No App group. Systolic BP was reduced from baseline in the App compared to No App group (-7.5 vs. -0.7 mmHg, p=0.12). No significant change was shown in the SCFLSD survey. Conclusions: Patients randomized to the app had a greater reduction in measures of sodium intake and systolic BP from baseline to 8 weeks compared to those that did not receive the application. Further studies are needed to confirm these results.