Morning blood pressure surge is associated with serum gamma-glutamyltransferase activity in essential hypertensive patients

The phenomenon that blood pressure rises sharply in the morning is called 'Morning Blood Pressure Surge' (MBPS). Serum gammaglutamyltransferase (GGT) is a proinflammatory marker involved in the pathogenesis of cardiovascular diseases. Although both are novel cardiovascular risk factors associated with inflammation and atherosclerosis, the specific relationship between MBPS and serum GGT is unknown. This study investigates the relationship between MBPS and serum GGT activity in essential hypertensive patients. Totally, 320 hypertensive patients were recruited. Mean MBPS was 17.0 +/- 12.9 mm Hg. MBPS was positively correlated with age (r = +0.222, P<0.0001), body mass index (r = +0.132, P = 0.018), GGT (r = +0.271, P<0.0001), daytime augmentation index adjusted for heart rate (AIx@75) (r = +0.140, P = 0.014), 24-h pulse wave velocity (PWV) (r = +0.143, P = 0.014) and daytime PWV (r = +0.158, P = 0.007). From the 25th to 75th quartile of serum GGT, MBPS increased significantly (P-trend < 0.0001). In multivariate linear regression analysis, MBPS was independently associated with age (P = 0.002), dipping status (P<0.0001) and logGGT (P<0.0001). In conclusion, MBPS is independently associated serum GGT activity in essential hypertensive patients. This is the first study in the literature to demonstrate an independent and a dose-response relationship between the two novel cardiovascular risk factors, MBPS and serum GGT, in this patient population.