Impact of self-monitoring of salt intake by salt meter in hypertensive patients: A randomized controlled trial (SMAL-SALT)

Salt intake over reference level would result in elevated blood pressure (BP) and long-term morbidity. Salt meter is a device used to detect sodium content in daily food. This study aimed to evaluate the efficacy of salt-meter addition to dietary education. The authors conducted a randomized-controlled trial in hypertensive patients with uncontrolled BP (systolic BP >= 140 mmHg or diastolic BP >= 90 mmHg). Patients were randomized to receive salt meter plus dietary education (group A) or education only (group B), and followed up for 8 weeks. The primary endpoint was change in 24-h urinary sodium excretion. Changes in BP, salt taste sensitivity, cardio-ankle vascular index (CAVI) were also analyzed. There were total number of 90 patients who had complete follow-up, 45 in each group. Mean age was 62.9 years and 53% were females. Mean baseline 24-h urine sodium was 151.6 mmol/24 h and mean SBP and DBP were 152.8 and 83.4 mmHg, respectively. Baseline characteristics were similar between two groups. At 8 weeks, mean change in urine sodium were -31.83 mmol/24 h and 0.36 mmol/24 h in group A and group B, respectively (p = .006). Mean decrease in BP were SBP, 14.44 versus 8.22 mmHg (p = .030), and DBP 5.53 versus 1.93 mmHg (p = .032). The salt sensitivity was improved more in group A. There was no different between change in CAVI. From this study, salt meter in conjunction with dietary education, for self-monitoring of salt intake is superior to education alone in hypertensive patients, and provided better blood pressure control. Salt meter should be considered in uncontrolled hypertensive patients.