Reducing Salt Intake Through Urinary Na/K Ratio Self-Monitoring

Self-monitoring with the urinary Na/K ratio meter, ≥3 times in a day, may be effective in lowering salt intake among patients who find it challenging to reduce their salt consumption, according to findings of a single center, non-randomized controlled study published in the journal Hypertension Research.1

This study examined the effectiveness and feasibility of a self-monitoring intervention in 160 patients with chronic kidney disease, hypertension, or heart disease who find it hard to reduce their salt consumption. A Na/K ratio meter that measured the urinary sodium/potassium (Na/K) ratio was utilized for this purpose. All the selected participants received follow-up care at the outpatient clinic of Dokkyo Medical University Nikko Medical Center in the city of Nikko in Japan.

The 80 participants in the treatment (T) group received the device to measure their urinary Na/K ratio for a mean duration of 25.1 days. They were instructed to measure it for a minimum of thrice daily and keep it below 2.0, while the control group of 80 subjects was not given the Na/K ratio meter. Both groups received salt reduction education and guidance about home blood pressure measurement.

Almost half (48.8%) of the T group patients could achieve three measurements per day over a mean follow-up period of 13 months. Self-monitoring with the urinary Na/K ratio meter led to a significant reduction in salt intake, which decreased by 1.9 g/day by the second visit (p < 0.001). No change was evident in the control group.

The Na-to-K ratio is now increasingly being recognized as a more reliable indicator of the risk of cardiovascular diseases (CVD) and CVD-related mortality than measuring either Na or K intake individually. Urinary Na-to-K ratio has demonstrated a strong predictive value for hypertension and CVD2 and thus salt intake. It is easier to measure and also obviates the inconvenience of collecting 24-hour urine samples without any loss of urine.

 References

 1.   Shimoyama M, et al. Effects of salt intake reduction by urinary sodium to potassium ratio self-monitoring method. Hypertens Res. 2024 Jul;47(7):1852-1860. doi: 10.1038/s41440-024-01655-1.

2.   Mirmiran P, et al. Urinary sodium-to-potassium ratio: a simple and useful indicator of diet quality in population-based studies. Eur J Med Res. 2021 Jan 6;26(1):3. doi: 10.1186/s40001-020-00476-5.