Restricting salt intake is considered important in the treatment of hypertension, and knowledge of the profile of salt and potassium (K) intakes is required in outpatients with hypertension. We collected spot urine from outpatients to determine urinary sodium (Na) and K excretion values and urinary creatinine to calculate daily salt and K intakes.Design and Method:
Spot urine from outpatients with hypertension (n = 377) or other diseases (n = 282) was collected when they presented to our hospital to receive medical examination from morning to noon. Urinary Na and K levels were determined, and daily excretion values were calculated based on the urinary Na (mEq/L) or K (mEq/L) values, body weight (BW, kg), height (cm), urinary creatinine value (mg/dl), age (years) and sex, according to previously reported method.Results:
Urinary Na and K excretion values were significantly lower in patients with hypertension (Na, 188.9 ± 3.9 mEq/day; K, 46.7 ± 0.7 mEq/day) than in patients with other diseases (Na, 204.5 ± 4.7 mEq/day; K, 50.1 ± 0.9 mEq/day). Body mass index was significantly higher in patients with hypertension (23.8 ± 0.2 kg/m2) than in patients with other disease (22.8 ± 0.2 kg/m2). Age did not differ significantly between groups (patients with hypertension, 72.0 ± 0.6 years; patients with others, 71.9 ± 0.8 years). Urinary Na and K excretion values correlated negatively with age and positively with body weight and BMI in both groups.Conclusions:
Lower Na excretion values in patients with hypertension might be attributable to effective education about the importance of lowering salt intake. On the other hand, lower K excretion suggests lower K intake, which might act to increase blood pressure. Education on this issue may help to increase K ingestion and body weight might be decreased. A simple method to determine 24-h urinary Na and K excretion in outpatients is useful for clinical application.