This study aims to explore the association between salt intake, knowledge of salt intake and blood pressure in Portuguese hypertensive patients.Design and method:
Data were collected from a cross-sectional sample involving 112 patients that were followed at a hypertension consultation at hospital. Data collection comprised interviewer-administered questionnaires about demographics and knowledge, attitudes and behaviors related to salt, followed by a physical examination (weight, height and blood pressure) and a single 24-hour urine collection. The 24-hour urine collection was analyzed for volume (ml/d), urinary creatinine (mg/day) and urinary sodium (mEq/day). For 24-hour urine collection validation, quality control was used calculating the coefficient of creatinine excretion in relation to body weight according to age group.Results:
Hypertensive patients with valid urine collections were 77 (38 males) with mean age 58.2 ± 14.7 years old, without gender differences (p = 0.575). The blood pressure control rate was 32.5% (mean systolic blood pressure was 147.5 ± 21.1 mmHg and diastolic blood pressure was 83.8 ± 11.4 mmHg). Of the subjects, 93.5% had salt intake higher than the 5 g/d recommended by World Health Organization. Mean salt intake was 10.2 ± 3.7 g/d, without differences between sex (p = 0.102) and with a positive association with BMI (r = 0.240, p = 0.035). Besides 97.4% of the subjects knew that excessive salt intake can result in hypertension, only 2.5% knew the daily recommended salt intake and 97.3% consider that daily ingest little or the right amount of salt. Also, 94.8% of patients recognize that try to reduce salt intake and the strategies adopted include reduce salt added during cooking (67.5%), avoid consume high salt products (13.0%), use herbs and spices to substitute salt during cooking (5.2%).Conclusions:
This study shows low rate of blood pressure control in a Mediterranean sample of hypertensive patients. Although patients were knowledgeable about the adverse effects of salt, low rate knew the daily intake recommended value and the majority of subjects present a misleading perception of actual salt intake. Increased knowledge about recommended salt intake and individual guidance including information about sodium excretion could be important for reducing salt intake in hypertensive patients.