Abstract-The prognostic value of sleep blood pressure reported by recent studies is variable. Our aim was to examine the relationship of sleep blood pressure, measured by 24-hour ambulatory blood pressure monitoring, with all-cause mortality. We studied a cohort of 3957 patients aged 55Ϯ16 (58% treated) referred for ambulatory monitoring (1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005) Key Words: ambulatory blood pressure monitoring Ⅲ dipping Ⅲ mortality Ⅲ cohort Ⅲ sleep blood pressure D ata generated by 24-hour ambulatory blood pressure monitoring (ABPM) have been used to predict cardiovascular morbidity, as well as cardiovascular and all-cause mortality. [1][2][3][4][5][6][7][8][9] There is mounting evidence that this predictive ability is in part unrelated to clinic blood pressure (BP) measurements. Conceivably, ABPM reflects physiological states that are not captured by resting clinic measurements. 9 Moreover, ABPM reduces the influence of the measurement itself on BP values, namely the white-coat effect. In addition, ambulatory monitoring may unmask abnormal BP values that were not detected in the office. Thus, it is expected that ABPM would predict mortality above and beyond clinic measurements. There is still debate, however, whether in reality this is indeed the case and whether the use of this burdensome technique in clinical care is justified and contributes to patient management. 5 Another issue under debate concerns which component of the 24-hour ambulatory monitoring incorporates the most valuable prognostic information. Measurements taken during the waking state reflect, in part, physical activity, which may differ within and between patients. Thus, we hypothesized that, compared with awake BP, sleep measurements would relate to prognosis in a more profound way. Indeed, some 1,3,5,7,10,11 but not all 2 of the outcome studies have suggested this previously.In this study, we investigated all-cause mortality among patients who underwent ambulatory monitoring in a single center since 1991. We highlight sleep BP data identified by recorded sleeping periods, including afternoon naps. 12 We show that sleep BP, as well as nocturnal BP reduction (dipping, a somewhat controversial and infrequently studied topic 7,9,10,13 ) have independent predictive power. Methods Study PopulationData were extracted from our entire ABPM service database, from 1991 through 2005. All of the patients were included, except those Ͻ16 years old, pregnant women, and subjects with poor-quality ABPM (Ͻ50 valid measurements). Patients were referred for standard clinical indications at the discretion of the referring physician (mainly primary care practitioners, who have been shown to use ABPM for appropriate indications 14 ). We were not involved in the clinical care of these patients. Baseline data collected included demographic characteristics (age: 55 years [range: 16 to 93 years], sex (53% female), ethnicity (94% Jewish and 6% non-Jewish, predominantly Moslem Arabs), height (1.67 m; range...

Background: Although it has been somewhat overlooked, resting heart rate is an established predictor of cardiovascular and noncardiovascular outcome. We assessed the determinants and mortality associations of heart rate measured during ambulatory blood pressure monitoring (ABPM) to evaluate its informativeness during activity and sleep. Methods: We studied a cohort of 3957 patients aged 55 ± 16 (mean ± SD) years (58% treated for hypertension) who were referred for ABPM during 1991 to 2005. Heart rate nondipping was defined as follows: (awake value−sleep value)/awake valueϽ0.1. Linear and logistic regression models assessed covariate associations with ambulatory heart rate indices. All-cause mortality was analyzed by Cox proportional hazards modeling. Results: Female sex, body mass index (calculated as weight in kilograms divided by height in meters squared), and treated diabetes were positively related to awake and sleep heart rate, whereas age and treated hypertension were inversely associated. All these variables were associated with lower sleep-related heart rate dipping magnitude. Multivariate-adjusted odds ratios (95% confidence intervals) for heart rate nondipping were 1.02 (1.02-1.03) per year of age; 1.05 (1.03-1.06) for body mass index; 1.39 (1.20-1.60) for women; 1.30 (1.12-1.51) for nappers; 2.19 (1.87-2.57) for treated hypertensive patients; and 1.38 (1.09-1.76) for treated diabetic patients. Mortality analysis according to deciles of the different heart rate variables showed a robust linear relationship only for heart rate dip and a hazard ratio of 2.67 (1.31-5.47) for the lowest vs the highest decile. Conclusions: In clinical practice, ambulatory heart rate adds prognostic information beyond that of other ABPM predictors. Heart rate measures during sleep, and in particular the absence of dipping of heart rate to sleep levels, were independently associated with all-cause mortality.

In a group of consecutive subjects referred for ambulatory BP monitoring, masked hypertension was found to be as common as isolated clinic hypertension. Masking was correlated with male sex, young age, and higher awake heart rate, thus suggesting a causal relationship with greater daytime physical activity. The linear association of the masking and the white-coat effects to clinic BP suggests that regression toward the mean may partially explain these phenomena.

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Abstract-Nondipping, ie, failure to reduce blood pressure by Ն10% during the night, is considered an important prognostic variable of 24-hour ambulatory blood pressure monitoring. However, some people wake up at night to urinate. Usually, 24-hour ambulatory blood pressure monitoring-derived blood pressure includes these rises in the nighttime blood pressure mean. We identified 97 subjects undergoing 24-hour ambulatory blood pressure monitoring who reported waking up at night to urinate. We assessed the 24-hour ambulatory blood pressure monitoring first using total daytime and total nighttime means and then using actual daytime awake and nighttime asleep (as reported by the patient) means. Nocturnal decline in blood pressure was 14.4Ϯ8.5/11.8Ϯ6.1 mm Hg with the first method and 17.1Ϯ8.3/13.8Ϯ5.9 mm Hg with the second one (PϽ0.00001). Although the absolute difference between the nocturnal blood pressure declines calculated by the 2 methods was small, the effect on nocturnal dip was profound. Average systolic blood pressure dipping was 10.1% by the total day-total night method and 12.0% by the actual day awake-night asleep method (PՅ0.00001), and that of diastolic blood pressure was 14.2% and 16.7%, respectively (PՅ0.00001). The prevalence of systolic blood pressure nondipping decreased from 42.2% by the first method to 31.9% by the second method (PՅ0.0056), and that of diastolic blood pressure nondipping decreased from 22.6% to 11.3% (PՅ0.00001). Inclusion of awake blood pressure measurements during the night obscured the normal dipping pattern in people who woke up to urinate. Thus, taking into account people's actual behavior increases the accuracy of the results.