Long-term compliance with salt restriction assessed using the spot urine method in Japanese cardiology outpatients

Abstract

The purpose of this study was to evaluate long-term compliance with salt restriction in Japanese cardiology outpatients assessed by spot urine measurements. A total of 466 patients (72 ± 10 years old, 216 females) who visited a cardiology outpatient clinic and were followed for at least 1 year were included in this study. Daily dietary salt intake was estimated based on the sodium and creatinine concentrations determined by spot urine at the time of enrollment, during an 8-26 week follow-up and at a long-term follow-up (>1 year). The average follow-up duration was 2.2 ± 0.6 (1.0-3.4) years after enrollment, and spot urines were collected 5.2 ± 2.8 times after 1 year. The baseline estimated salt excretion was 9.6 ± 2.7 g per day, which was reduced to 8.7 ± 2.3 g per day (P<0.01) at 8-26 weeks and remained unchanged at the long-term follow-up (8.9 ± 2.0 g per day, P = 0.36 vs. 8-26 weeks, P < 0.01 vs. baseline). The percent of patients who achieved an average salt excretion<6.0 g per day was unchanged from baseline (6.9% vs. 7.7%, P = 0.61). Among several variables (gender, age, body weight, salt excretion at enrollment) that might affect the incidence of salt excretion <6.0 g per day, salt excretion at baseline was the only determinant of successful salt restriction (P<0.01). In conclusion, compliance with salt restriction, assessed using a spot urine method, was maintained over the long term; however, achieving salt reduction to the level recommended by the guidelines remains a challenge.

Effects of single-session dietary counseling by dieticians on salt reduction in cardiology outpatients who consumed large amounts of salt

“…A total of 72 patients were included in this study. The baseline characteristics of the patients are presented in Table I; these characteristics were similar to those reported in previous studies (3,4), with the exception that the salt excretion levels were considerably higher. There were no differences in the characteristics between patients who received dietary counseling and those who did not (the control group).…”

“…The present study has certain limitations. First, the estimation of daily urinary salt excretion using a spot urine sample may be less accurate than that using 24-h urine collection, as previously noted (3,4). However, it is difficult to collect 24-h urine in real-world practice.…”

“…However, salt reduction is challenging to achieve in the real world, particularly in countries in which salt consumption is extremely high, such as Japan. We have previously reported that the estimation of salt intake using the spot urine method may be a useful tool to motivate patients to reduce their salt intake for 8-26 weeks (3), and the efficacy of this method was found to be maintained at long-term (up to 2 years) follow-up (4). However, the percentage of patients who could achieve a reduction in salt intake to the recommended level was very low (<10-15%) (3,4).…”

“…We have previously reported that the estimation of salt intake using the spot urine method may be a useful tool to motivate patients to reduce their salt intake for 8-26 weeks (3), and the efficacy of this method was found to be maintained at long-term (up to 2 years) follow-up (4). However, the percentage of patients who could achieve a reduction in salt intake to the recommended level was very low (<10-15%) (3,4). In particular, patients who habitually consume large amounts of salt at baseline find it difficult to reduce salt intake to the recommended level regardless of gender, age and body weight (4).…”

“…However, the percentage of patients who could achieve a reduction in salt intake to the recommended level was very low (<10-15%) (3,4). In particular, patients who habitually consume large amounts of salt at baseline find it difficult to reduce salt intake to the recommended level regardless of gender, age and body weight (4). This might be partly explained by the lack of dietary counseling by expert dietitians in the majority (93%) of the patients included in the previous study (4).…”