Associations of vitamin D with coronary revascularization and heart rate variability in hypertensive patients

Even though substantial evidence has found that vitamin D deficiency correlates to risk factors for cardiovascular disease (CVD), few studies have shown how vitamin D affects coronary revascularization and heart rate variability (HRV). We aimed to explore the connection between vitamin D levels with coronary revascularization and HRV in hypertensive patients.

A total of the 250 eligible participants with hypertension hospitalized at the Department of Cardiology, Sixth Medical Center of Chinese PLA General Hospital was consecutively recruited. The status of vitamin D is measured utilizing serum 25-hydroxyvitamin D₃ [25(OH)D₃] concentrations. The primary endpoints were defined as patients undergoing coronary revascularization treatment. The secondary endpoints were defined as the variation in HRV. HRV indices were recorded in participants using a 24-h Holter electrocardiogram (ECG). In addition, direct renin concentrations and plasma aldosterone concentrations were measured in the supine and standing positions.

In the study, 165 eligible patients assigned to the vitamin D deficiency [25(OH)D₃ < 20 ng/ml] group and 85 to the vitamin D non-deficiency[25(OH)D₃ ≥ 20 ng/ml] group. In both univariate logistic regression analysis (OR: 2.46, 95% CI: 1.06-5.68; P = 0.036) and multivariate logistic regression analysis (OR: 2.54, 95% CI: 1.02-6.33; P = 0.046), the 25(OH)D₃ < 20 ng/ml demonstrated to be a significant risk factor of primary endpoints for those hypertensive patients. Receiver operating characteristic curve (ROC) analysis showed the multivariable-adjusted model for predicting primary endpoints in patients with hypertension, with an area under the curve (AUC) of 0.73 (95% CI: 0.64-0.82, p < 0.001). Regarding secondary endpoints, the HRV indexes such as standard deviation of normal-to-normal (NN) intervals (SDNN) (P = 0.04), standard deviation of the averages of NN intervals in all 5-min segments (SDANN) (P = 0.03), and Triangle indexes values (P = 0.02) were significantly different in the two groups. Finally, we observed that hypertensive patients with vitamin D deficiency had significantly greater aldosterone and aldosterone-to-renin ratio (ARR) values than those having vitamin D non-deficiency.

Vitamin D deficiency was prevalent in hypertensive patients and was independently associated with the risk of coronary revascularization. Vitamin D deficiency also affects HRV and ARR values in hypertensive patients.