Masked Hypertension, Endothelial Dysfunction, and Arterial Stiffness in Type 2 Diabetes Mellitus: A Pilot Study

BACKGROUND The aim of this study was to assess the relationship between masked hypertension (MHT) and vascular damage in patients with type 2 diabetes. METHODS The study subjects were patients with type 2 diabetes who were normotensive based on blood pressure (BP) measurement in the clinic (n = 80) without antihypertensive drugs and free of retinopathy, macroalbuminuria, overt cardiovascular disease. Subjects underwent 24-h ambulatory blood pressure monitoring (ABPM), measurement of flow-mediated dilatation (FMD), and brachial-ankle pulse wave velocity (baPWV). Based on the results of ABPM, subjects with mean daytime systolic BP >= 135 and/or 85 mm Hg were defined as MHT and their clinical data were compared with those of normotensive patients (NT). The data were also compared with those of type 2 diabetic patients with hypertension (HT) as measured in the clinic (n = 32). RESULTS MHT was detected in 47.5% of the study subjects with normotension at clinic (n = 38). Impaired FMD (5.65 +/- 2.00% for NT, 4.26 +/- 1.88% for MHT, 3.90 +/- 1.71% for HT, P < 0.001) and higher baPWV (1,514.2 +/- 212.7 cm/s for NT, 1,749.9 +/- 339.7 cm/s for MHT, and 1,768.6 +/- 302.8 cm/s for HT, P < 0.001) were similarly noted in patients with MHT and HT compared with NT. Multivariate regression analysis indicated that daytime systolic BP measured by ABPM, the estimated duration of diabetes and serum triglycerides were significantly associated with FMD and daytime systolic BP measured by ABPM, not systolic BP at clinic, age, and HbA(1c) were significantly associated with baPWV. CONCLUSIONS Given that patients with impaired FMD and higher baPWV are known to be at higher risk of cardiovascular disease, our data suggest that type 2 diabetic patients with MHT could be also at increased risk of cardiovascular disease.