Effectiveness of a Sodium Intake Monitoring Smartphone Application (NamakBan) on Clinical Outcomes of Patients Diagnosed With Hypertension: A Randomized Clinical Trial

Aim: To evaluate the effectiveness of NamakBan, a smartphone application for monitoring sodium intake, on blood pressure, dietary sodium consumption, urinary sodium-to-potassium ratio and hospitalization in adults with primary hypertension. Design: We conducted a parallel randomized clinical trial at the specialized hypertension clinic of Shahid Modarres Hospital in Tehran, Iran. Methods: Between April 1, 2024, and September 20, 2025, 88 patients with physician-diagnosed primary hypertension were randomized (1:1) to receive standard clinic care (control, n = 44) or standard care plus the NamakBan app (intervention, n = 44). The app (Android) allowed repeated self-reporting of blood pressure and salt intake, medication logging, and PDF output for monitoring. Outcomes were assessed at baseline, 1 month and 2 months. Primary outcomes were systolic and diastolic blood pressure; secondary outcomes were self-reported dietary sodium intake, urinary Na+/K+ ratio and readmissions. Results: Baseline characteristics were balanced. Compared with the control, the experimental group showed greater reductions in systolic blood pressure and diastolic blood pressure. Self-reported daily sodium intake declined more in the experimental arm than in the control. Urinary Na+/K+ ratio decreased within the experimental group over time, but between-group differences were not significant. No hypertension-related hospital readmissions were recorded in the intervention group, whereas four readmissions occurred in the control group; however, this difference was not statistically significant. Conclusions: In this RCT, the NamakBan application, used alongside usual care, was associated with modest but statistically significant improvements in systolic blood pressure, diastolic blood pressure and self-reported sodium intake over 2 months. However, the objective urinary sodium-to-potassium ratio did not differ between groups. The findings should therefore be interpreted with caution: dietary sodium was assessed via unblinded self-report, follow-up was limited to 2 months, the trial was single-centre and the application was available only on Android. Implications for Patient Care: Integration of such applications into routine nursing and clinical follow-up may improve outcomes and potentially reduce hypertension-related hospital readmissions. Impact: What problem did the study address?: Inadequate monitoring of dietary sodium intake and limited patient engagement in self-management contribute to poor blood pressure control in adults with primary hypertension. Few randomized trials of sodium-focused applications report an objective biochemical measure alongside self-reported intake or health-service outcomes such as readmission. What were the main findings?: Use of the NamakBan smartphone application, in addition to usual care, led to significant reductions in systolic and diastolic blood pressure and an improvement in self-reported sodium intake. No hypertension-related hospital readmissions were observed in the intervention group; however, the between-group difference was not statistically significant. Where and on Whom Will the Research Have an Impact?: This research will benefit adults with primary hypertension and inform nursing practice and outpatient hypertension care, particularly by integrating mobile health interventions into routine clinical follow-up and patient education. Reporting Method: Consolidated Standards of Reporting Trials (CONSORT). No Patient or Public Contribution. Trial Registration: Iranian Registry of Clinical Trials (IRCT): registration code IRCT20240207060927N1. © 2026 The Author(s). Nursing Open published by John Wiley & Sons Ltd.