Association of urinary sodium/potassium ratio with structural and functional vascular changes in non-diabetic...

Studies aiming to associate the sodium/potassium (Na/K) ratio with hypertension use 24-hour urinary excretion as a daily marker of ingestion. The objective of this study was to evaluate the association between urinary Na/K ratio and structural and functional vascular alterations in non-diabetic hypertensive patients. In hypertensive patients (n = 72), aged between 40 and 70 years, both sexes (61% women), in use of hydrochlorothiazide, we measured blood pressure, 24-hour urine sample collection, assessment of carotid-femoral pulse wave velocity (cf-PWV, Complior), central hemodynamic parameters (SphygmoCor), and post-occlusive reactive hyperemia (PORH). The participants were divided according to the tertile of 24-hour urinary Na/K ratio. Each group contained 24 patients. Systolic blood pressure was higher in T2 (133 ± 9 vs 140 ± 9 mmHg, P = .029). C-reactive protein (CRP) presented higher values in T3 as compared to T1 [0.20(0.10-0.34) vs 1.19 (0.96-1.42) mg/dL, P < .001]. Higher values in T3 were also observed for aortic systolic pressure (aoSP) [119(114-130) vs 135(125-147) mmHg, P = .002] and cf-PWV (9.2 ± 1.6 vs 11.1 ± 1.5 m/s, P < .001). The urinary Na/K ratio presented significant correlations with proteinuria (r = .27, P = .023), CRP (r = .77, P < .001), cf-PWV (r = .41, P < .001), and post-occlusive reactive hyperemia on cutaneous vascular conductance (PORH CVC) (r = -.23, P = .047). By multivariate linear regression, it was detected an independent and significant association of cf-PWV with urinary Na/K ratio (R²  = 0.17, P < .001) and PORH CVC with CRP (R²  = 0.30, P = .010). Our data indicated that increased urinary Na/K ratio in non-diabetic hypertensive patients was associated with higher degree of inflammation, raised peripheral and central pressure levels, and changes suggestive of endothelial dysfunction and arterial stiffness.