Procynostic value of circadian blood pressure changes in relation to differing measures of day and night

Although the prognostic value of the day-night blood pressure (BP) changes is established, the most appropriate method for defining day and night is undefined. We assessed the prognostic value of the day-night BP changes by using three definitions of day and night in 2,934 initially untreated hypertensive subjects who underwent 24-hour ambulatory BP monitoring Over a median follow-up period of 7 years. there were 356 cardiovascular events and 176 deaths Total cardiovascular events and all-cause mortality were similarly higher in non-dippers (night/day ratio of systolic BP >10% or >0%) than in dippers regardless of the definition of day and night Ill a receiver-operated characteristic (ROC) curve analysts of the night/day ratio of systolic BP oil the occurrence of events, the ares under the ROC curve did not differ among the different definitions of day and night (large fixed-clock intervals. narrow fixed-clock intervals, chary) for both total cardiovascular events (061 [95% confidence interval (Cl). 0 58 to 0 641 0 61 [95% Cl. 0.57 to 0.63]. 0 62 [95% Cl 0.58 to 0 65], respectivelv P = 0.20) and all-cause mortality (0 65 [95% CI 0 61 to 0 70]. 0.64 195% CI 0 60 to 0.69]. 0 65 195% Cl: 0 61 to 0 70]. respectively: P = 0 78). me prognostic value of the diurnal BP changes is comparable when using different clock-dependent or Independent definitions of day and night. (C) 2008 American Society of Hypertension. All rights reserved.