Serum interleukin-18 levels are associated with non-dipping pattern in newly diagnosed hypertensive patients.

Abstract

Interleukin-18 (IL-18), a pro-inflammatory cytokine, increases inflammation in the endothelium. Increased inflammation plays an important role in the development of hypertension (HT). IL-18 level is higher in hypertensives than normotensives. To investigate the relationship between IL-18 level and diurnal blood pressure (BP) variations in newly diagnosed HT patients. This prospective study included 130 subjects referred to outpatient cardiology clinic with an initial diagnosis of HT. The patients were classified as dipper HT (n = 40), non-dipper HT (n = 50), and normotensive (control, n = 40) according to 24-hour ambulatory BP monitoring. All subjects underwent blood sampling after 12 hours of fasting and transthoracic echocardiography. The serum IL-18 level was significantly higher in the patient group compared with the controls (195.17 ± 93.00 mg/dl vs. 140.75 ± 71.11 mg/dl, P < 0.01) and also in the non-dipper group than in the dipper group (217.3 ± 96.90 mg/dl, 167.5 ± 80.79 mg/dl, P = 0.011). IL-18 level was positively correlated both the night-time SBP and DBP levels (r = 0.29, P = 0.02 and r = 0.34, P < 0.01, respectively). On multivariate linear regression analysis, left atrium diameter, left ventricular mass index, and serum IL-18 level were independent predictors of non-dipping pattern in newly diagnosed HT patients. Higher IL-18 level was particularly associated with an increase in the night-time BP levels. IL-18 can be used as a predictor for non-dipper HT in newly diagnosed HT patients.