Ambulatory blood pressure monitoring in normotensive and hypertensive type 2 diabetes. Prevalence of impaired diurnal blood pressure patterns

To assess the prevalence of an impaired diurnal blood pressure (BP) pattern in a population of both normotensive and hypertensive diabetics, noninvasive ambulatory BP monitoring (SpaceLabs 5200, Redmond, WA) was performed in 96 outpatients with type 2 diabetes (47 normotensives and 48 hypertensives) and in 103 control subjects without diabetes (50 normotensives and 53 hypertensives). Mean 24 h and daytime (06:00 to 22:00) BP and heart rate (HR) were not statistically different in diabetic patients compared to nondiabetic ones. Nighttime (22:00 to 06:00) BP and HR tended to be higher in both normotensive and hypertensive diabetics, although not significantly. Heart rate, diastolic BP (DBP), and especially the nocturnal systolic BP (SBP) decrease, were less marked in both normotensive and hypertensive diabetics, with a consequent increase in rate-pressure. A significant correlation was found between the percent decrease in nighttime SBP and the decrease in orthostatic SBP in casual BP measurements. The analysis of individual recordings allowed us to detect an impaired circadian pattern (the disappearance of the nocturnal BP decrease or a paradoxical BP increase) in 30% of the normotensive and 31% of the hypertensive diabetics (v 6% of the normotensive and 6.4% of the hypertensive nondiabetic subjects). As the absence of a nocturnal BP fall has been associated with the increased prevalence of left ventricular hypertrophy and atherosclerotic cardiovascular disease, its detection by ambulatory monitoring might be of prognostic and therapeutic importance