Effects of salt intake reduction by urinary sodium to potassium ratio self-monitoring method

Effective and feasible educational methods are needed to control salt intake. We performed a single-center, non-randomized controlled study to investigate the effectiveness and feasibility of self-monitoring using a urinary sodium/potassium (Na/K) ratio-measuring device in patients with difficulty in reducing salt intake. This study included 160 patients with hypertension, chronic kidney disease, or heart disease who were followed up in the outpatient clinic of the Dokkyo Medical University Nikko Medical Center. Urinary Na/K ratio measuring Na/K ratio meter were loaned for 2-6 weeks to the treatment (T) group (n = 80) and not to the patients in the control (C) group (n = 80). In the T group, patients were instructed to measure the urinary Na/K ratio at least three times a day and maintain a Na/K ratio below 2.0. Salt reduction education and home blood pressure measurement guidance continued in both groups. The mean device loan period in the T group was 25.1 days, the mean number of measurements was 3.0 times/day, and the proportion of patients achieving three measurements per day was 48.8% (39/80). Self-monitoring using the urinary Na/K ratio meter successfully reduced salt intake by -1.9 g/day at the second visit (p < 0.001) in the T group. In contrast, no change was observed over time in the C group. Self-monitoring using the urinary Na/K ratio meter successfully reduced salt intake in patients with difficulty reducing salt intake.