THE ROLE OF HIGH DIETARY SALT INTAKE IN DEVELOPMENT OF RESISTANT HYPERTENSION

Abstract

Objective: Aim of the study: evaluate salt-taste sensitivity and daily salt intake in patients with resistant arterial hypertension (RAH) during antihypertensive treatment (AHT). Design and method: The study included 137 patients with high risk arterial hypertension in average age 56.6 ± 9.8 years. All patients took triple combination AHT with diuretic, RAAS-blocker and calcium antagonists during 3 months. After 3 months therapy 83.2% patients were achieved goal BP, 16.8% of them were resistant to triple combination AHT. Thus, patients divided into 2 groups: RAH (n = 23) and non-RAH (n = 114) and continued AHT with recommendation to reduce dietary salt intake to 5–6 g/24 h. Salt-taste sensitivity (STS) evaluation, implemented R.Henkin method with using sodium chloride in different concentration: from 0.01% to 1.28%. The patients divided to 3 STS thresholds: low (0.01%-0.08% NaCl), medium (0.16% NaCl), and high thresholds (>0.32% NaCl). Daily salt intake was calculated by urinary sodium excretion level multiply 2.55, before and after treatment. Results: Patients with RAH characterized with significantly high systolic and diastolic BP (SBP/DBP): 178.1 ± 15.4/103.3 ± 10.1 mmHg vs. 158.9 ± 13.3/98.7 ± 7.25 mmHg in non-RAH group (p = 0.0001). STS test was shown prevalence high threshold of STS in RAH patients (high/medium 90.5%/9.5% χ2 = 46.7, p = 0.0001) in comparison with non-RAH group (high/medium/low 74%/12%/14% χ2 = 130.4, p = 0.0001) with significant difference in sodium chloride concentration: 0.41 ± 0.17% vs. 0.3 ± 0.18%, p = 0.01, for RAH and non-RAH groups respectively. Before AHT daily urinary sodium excretion rate was high in RAH patients (5.66 ± 2.49 g/24 h vs. 4.5 ± 2.54 g/24 h, p = 0.056), that corresponded to 14.4 g and 11.47 g daily salt intake in RAH and non-RAH respectively. During 6 months therapy BP significantly decreased in both groups, but in non-RAH group BP reducing was better with statistical difference: 128.3 ± 11.46/80.8 ± 7.9 mmHg vs. 122.4 ± 6.0/76.36 ± 8.5 mmHg, p = 0.0001 and p = 0.022 for SBP and DBP respectively. Daily urinary sodium excretion rate was significantly decreased only in non-RAH patients in comparison with RAH patients with statistical difference: 3.8 ± 2.29 g/24 h vs. 5.46 ± 2.7 g/24 h (p = 0.006). Conclusions: Patients with RAH characterized with high STS threshold and dietary salt intake. During six monthly optimal AHT, BP significantly reducing in both groups, but in non-RAH patients BP and daily urinary sodium excretion was statistically lower.