Spot urine-guided salt reduction is effective in Japanese cardiology outpatients

Dietary salt restriction is recommended for the prevention of cardiovascular disease in patients with hypertension and heart failure as well as in the general population. However, salt reduction is very difficult without knowing the daily salt intake of individual patients. A total of 524 subjects (72 ± 10 year old, 246 female) who visited an outpatient cardiology clinic were included in this study. Daily dietary salt intake was estimated based on the sodium and creatinine concentrations of spot urine at the time of enrollment and during follow-up for 8-26 weeks. The attending physicians explained the individual data to the patients and encouraged them to reduce their salt intake through simple counseling. The baseline estimated salt excretion was 9.6 ± 2.7 (range: 3.5-22.1) g per day, which decreased to 8.7 ± 2.3 (3.7-18.0) g per day during follow-up. The systolic blood pressure decreased from 127.0 ± 15.4 (range: 80-170) to 125.6 ± 14.5 (80-172) mm Hg (P=0.026), and the diastolic blood pressure decreased from 73.4 ± 11.0 (range: 40-106) to 71.5 ± 10.8 (50-102) mm Hg (P<0.001). In conclusion, the estimation of salt intake by spot urine was a useful method for motivating patients to reduce their salt intake; however, achieving salt reduction to the level recommended by the guideline could be a challenge.