Day-by-day variability in self-measured blood pressure at home

Abstract

To investigate variability in self-measured home blood pressure (HBP) and its effects on carotid artery atherosclerosis and endothelial function in normotensive and mild-moderate hypertensive individuals. This is a cross-sectional study. HBP monitoring over 7 consecutive days, carotid artery ultrasound, and brachial artery flow-mediated dilation (FMD) were performed in 314 normotensive, prehypertensive, and mild-moderate hypertensive volunteers. Variability in HBP was assessed by the SDs of the daily BP average of the last 6 consecutive days. The plasma endothelin-1 (ET-1) level was tested using an enzyme-linked immunosorbent assay. The tendency of SD of systolic HBP increased significantly from the normotension to the moderate hypertension group. SD of systolic HBP was significantly correlated with carotid intima-media thickness (IMT) (r=0.569, P<0.001), stiffness parameter β (r=0.447, P<0.001), FMD (r=-0.636, P<0.001), and ET-1 (r=0.649, P<0.001). SD of diastolic HBP was also correlated with carotid IMT, stiffness parameter β, FMD, and ET-1, but the strength of the correlation was weaker than SD of systolic HBP (all P<0.001). After adjustment of all covariants, SD of systolic HBP was always significantly associated with carotid IMT, stiffness parameter β, FMD, and ET-1. Day-by-day variability in HBP increased with increasing BP level. This was significantly associated with carotid artery atherosclerosis and endothelial function in normotensive and mild-moderate hypertensive individuals. Day-by-day variability in HBP may serve as an important prognostic factor for atherosclerosis and endothelial dysfunction.