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

Abstract

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 70years, 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±9mmHg, 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±1.5m/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.