COMPLIANCE WITH LONG-TERM DIETARY SALT RESTRICTION IN HYPERTENSIVE OUTPATIENTS

Eighty hypertensive outpatients were recruited for a dietary salt rest riction program to examine long-term compliance. Twenty-four-hour urin e samples were collected repeatedly (7.9+/-2.6 times, mean+/-s.d.) dur ing a follow-up period of 6.4+/-1.7 years. After initial urine collect ion, nutritional education was carried out by dietitians to reduce die tary salt intake to 8 g/day or less. After every urine collection, the subjects were given advice by doctors on salt restriction, if necessa ry. The mean 24-hour urinary salt excretion (U-NaCl) and the mean urin ary salt/creatinine ratio (U-NaCl/U-Cr) varied considerably both among and within individuals. U-NaCl/U-Cr, but not U-NaCl, in females was s ignificantly higher than that in males, and in middle-aged subjects th an in young subjects. U-NaCl and U-NaCl/U-Cr tended to decrease in the summer. In spite of the repeated educational effort, neither U-NaCl n or U-NaCl/U-Cr was different in the first control samples from that in the last samples. When 57 subjects were divided into three groups acc ording to the urinary salt excretion level, U-NaCl was consistently hi gher during a follow-up period in the high-salt excretion group than i n the mid-salt excretion group, while U-NaCl in the low-salt excretion group was initially lower than, but finally similar to, that in the m id-salt excretion group. These results suggest that: (1) multiple 24-h our urine samplings are required to assess urinary salt excretion in i ndividuals; (2) the influence of age and sex should be taken into acco unt in interpreting U-NaCl/U-Cr; and (3) it seems difficult to achieve long-term dietary salt restriction as a non-pharmacologic treatment o f hypertension in an outpatient clinic.