The relationship between vitamin D levels and plasma renin activity in patients with arterial hypertension

The aim of the study was to evaluate plasma renin activity (PRA) and its relationship with the level of 25-hydroxyvitamin D (25 (OH) D) in the blood in patients with stage II arterial hypertension (AH). We examined 228 patients (186 women and 42 men, mean age 52,4 ± 7,6 years). They were divided into two groups, one (n = 51) with optimal vitamin D levels (25 (OH) D ≥30 ng/ml), the other (n = 177) with D-hypovitaminosis (25 (OH) D <30 ng/ml). In this group, PRA (0,88 [0,61, 1,80] ng/ml/h) and the level of parathyroid hormone (38.6 [26.3; 52.1] pg/ ml) were higher (p <0,05), than in the former group (0,56 [0,38; 1,09] ng/ml/h and 29.8 [21.6; 44.1] pg/ml respectively). In group 2, the nitrate/nitrite level (18,57 ± 6,56 µmol/l) and blood calcium (2,34 ± 0,15 mmol/l) were lower (p <0.05) than in group 1 (21,57 ± 6,92 µmol/l and 2.40 ± 0.18 mmol/l respectively). No significant differences in results of echocardiography between the groups was apparent. We documented negative correlation between PRA and serum 25(OH)D level. PRA showed weak negative correlation with endothelium-dependent vasodilation (R = -0,15; p = 0,05); this relationship became even more evident (R = -0,24; p = 0.007) in patients with D-hypovitaminosis but was insignificant in those having the optimal level of vitamin D. It suggests the influence of vitamin D on vascular endothelial function and PRA interaction with endothelium. PRA shows positive correlation with the left ventricular wall thickness, left ventricular myocardial mass and negative correlation with the left ventricular ejection fraction, both being more pronounced in patients with D-hypovitaminosis and reflecting the influence of PRA on the structural and functional state of the myocardium.