LowSalt4Life: A Mobile Application to Reduce Sodium Intake And Blood Pressure

A Just-In-Time Adaptive Mobile Application Intervention To Reduce Sodium Intake And Blood Pressure In Hypertensive Patients: LowSalt4Life

This research is being done to learn if a smartphone app with and without a just in time adaptive intervention (JITAI) can help patients with hypertension manage their sodium intake and improve their blood pressure.

Study Overview

• Status: Completed
• Conditions: Hypertension; Blood Pressure
• Intervention / Treatment: Behavioral: LowSalt4Life Application; Behavioral: Just-In-time Adaptive Intervention (JITAI)

Detailed Description

The primary and secondary outcomes will be determined in months 1 & 2. Participants will continue for another 4 months and during that time data for exploratory measures will be collected.

During the first 2 months of the study, a micro-randomized trial (MRT) will be performed within the App+JITAI group (N=200). This MRT is designed to learn which push notification messages effectively prompt the user to interact with the appropriate content within the mobile application.

• Study Type: Interventional
• Enrollment (Actual): 410
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Michigan
    • Ann Arbor, Michigan, United States, 48109
      • The University of Michigan

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Diagnosed with essential hypertension (HTN) by a medical provider and are on stable doses of antihypertensive therapy for at least three months prior to enrollment as documented in the electronic health record (EHR) and confirmed by participant self-report.
2. A smartphone with a compatible Apple or Android operating system installed and able to download and use LowSalt4Life app including accepting all permissions and willing to allow the mobile applications to send push notifications
3. A valid email address
4. Fluent in spoken and written English

Exclusion Criteria:

1. Unstable symptoms or markedly elevated blood pressure (BP) at enrollment (defined as systolic BP>180 mmHg, diastolic BP>120 mmHg)
2. Contraindication to a sodium restriction diet
3. An estimated sodium intake less than 1,500mg per day
4. Known secondary causes of HTN (e.g., adrenal insufficiency, pheochromocytoma)
5. Estimated glomerular filtration rate (EGFR) <30 or end-stage renal disease on dialysis
6. Heart failure
7. Inability to use Withings devices (blood pressure cuff and scale) due to equipment limitations or contraindications
8. Currently pregnant or intent to become pregnant during the study period

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: LowSalt4Life	Behavioral: LowSalt4Life Application; LowSalt4Life is a dietary sodium intervention mobile application that promotes lower sodium intake.
Experimental: LowSalt4Life + just-in-time adaptive intervention (JITAI)	Behavioral: LowSalt4Life Application; LowSalt4Life is a dietary sodium intervention mobile application that promotes lower sodium intake.; Behavioral: Just-In-time Adaptive Intervention (JITAI); LowSalt4Life is a dietary sodium application with a just-in-time adaptive intervention (JITAI) component enabled.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in systolic blood pressure (SBP)	SBP measured by a wireless home blood pressure monitor	Baseline, 2 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in weight over 2 months	Weight measured using wireless scale	Baseline, 2 months
Change in estimated sodium intake	As measured by the Block 2014 Food Frequency Questionnaire	Baseline, 2 months
Change in dietary nutrient intake	As measured by the Block 2014 Food Frequency Questionnaire	Baseline, 2 months
Changes in blood pressure (BP) medications	As measured by the electronic health record	Baseline, 2 months
Percent of participants at a goal blood pressure (BP)	Goal BPs are based on the American Heart Association blood pressure guidelines.	2 months

Collaborators and Investigators

• Sponsor: University of Michigan
• Collaborators: National Heart, Lung, and Blood Institute (NHLBI)
• Investigators: Principal Investigator: Brahmajee Nallamothu, University of Michigan

Study record dates

Study Major Dates

• Study Start (Actual): August 15, 2022
• Primary Completion (Actual): October 31, 2025
• Study Completion (Actual): October 31, 2025

Study Registration Dates

• First Submitted: May 24, 2022
• First Submitted That Met QC Criteria: May 24, 2022
• First Posted (Actual): May 27, 2022

Study Record Updates

• Last Update Posted (Estimated): November 18, 2025
• Last Update Submitted That Met QC Criteria: November 14, 2025
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Keywords: Dietary sodium
• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Hypertension
• Other Study ID Numbers: HUM00210954; 1R61HL155498-01A1 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: The aim is to prepare data for deposit into the National Heart, Lung, and Blood Institute (NHLBI) supported Biologic Specimen and Data Repositories Information Coordinating Center (BioLINCC).Unique research data be made available to the scientific community after the conclusion of a study. The de-identified analytic data will be prepared as SAS transport files or ASCII comma-delimited files with accompanying codebooks that describe the data and data structure. The redaction will employ best practices and will be consistent with National Heart, Lung, and Blood Institute data sharing policies.
• IPD Sharing Time Frame: Unique research data be made available to the scientific community after the conclusion of a study. No later than 3 years after the end of the study or 2 years after the main paper reporting the results of the trial, whichever comes first.
• IPD Sharing Access Criteria: The scientific community will have access to the data deposited into the National Heart, Lung, and Blood Institute (NHLBI) supported Biologic Specimen and Data Repositories Information Coordinating Center (BioLINCC). Researchers at institutions with a Federal Wide Assurance will be able to gain access to repository data by submitting a data access request in accordance with applicable policies.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; ICF

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No