Reference Values for 24-Hour Ambulatory Blood Pressure Monitoring Based on a Prognostic Criterion

Abstract

Abstract-Although reference values for ambulatory blood pressure (ABP) monitoring have been investigated in several population studies, these values were derived from cross-sectional observations and were based merely on the statistical distribution of blood pressure values. Therefore, we conducted a prospective cohort study to identify reference values for 24-hour ABP in relation to prognosis. We obtained measurements of 24-hour ABP for 1542 subjects (565 men) aged 40 years and over in a general population of a rural Japanese community and then followed-up their survival status. There were 117 deaths during the follow-up period (mean, 6.2 years). The association between baseline 24-hour ABP values and mortality, examined by the Cox proportional hazards regression model adjusted for possible confounding factors, showed a better fit with a second-degree equation than with a first-degree equation. On the basis of the results of this analysis, we identified the following reference values as the optimal blood pressure ranges that predict the best prognosis: 120 to 133 mm Hg for systolic blood pressure and 65 to 78 mm Hg for diastolic blood pressure. 24-Hour ABP values Ͼ134/79 mm Hg and Ͻ119/64 mm Hg were related to increased risks for cardiovascular and noncardiovascular mortality, respectively. This is the first report to propose reference values for 24-hour ABP based on a prognostic criterion. (Hypertension. 1998;32:255-259.)Key Words: blood pressure, ambulatory Ⅲ reference values Ⅲ mortality Ⅲ prospective studies Ⅲ Japanese population N oninvasive techniques for measuring ABP now make it possible to monitor blood pressure during activity and sleep and provide more reproducible information than casual (screening) blood pressure measurements.1-4 Target-organ damage and cardiovascular morbidity are more strongly correlated with ABP than with casual blood pressure. 3-12However, there is no consensus on the use of ABP to diagnose and manage hypertension, 3,4,[13][14][15][16][17] in part because reference values have not been established. Proposed reference values for ABPM are based on cross-sectional observations.18 -22 However, because the reference value must be the value that best predicts the risk of morbidity and mortality, a longitudinal study in a general population is needed to investigate the prognostic significance of the value.We initiated ABPM in the general population of a rural Japanese community 18 and have been monitoring the survival of these individuals since 1987. 23,24 The objective of the present study is to propose the reference values for 24-hour ABPM in relation to prognosis and to investigate the prognostic significance of the value. Methods DesignThe present report is based on a longitudinal observation of subjects who have been participating in an ABP measurement project in Ohasama, Iwate Prefecture, Japan, since 1987. The socioeconomic and demographic characteristics of this region and the details of the study project have been previously described. 18,23,24 The study protocol was approved ...

Ambulatory Blood Pressure and Mortality

“…15 Only 1 other large study has examined the relationship between ambulatory BP and mortality in a general population: the Ohasama study. 16 In this study, there was a U-shaped relationship between ambulatory BP and cardiovascular mortality. The reason for this discrepancy between the Ohasama study and our study may rely on inclusion criteria.…”

White coat hypertension is a cardiovascular risk factor: a 10-year follow-up study

“…10,11 Longitudinal results have been published by others both in normotensive and in hypertensive populations and they show the same relations as our prospective results. [17][18][19] The high event rate in the WCH group raises the important question of whether there is also a positive relation between WCE and cardiovascular morbidity rate in our population. This was not the case, neither if the referring doctor's OBP, nor if our own OBP were used to calculate the WCE.…”

Effect of Blood Pressure During the Acute Period of Ischemic Stroke on Stroke Outcome

“…7 There is a possibility of a J-shaped relationship between BP and stroke outcome, with poorer outcome in the groups with extreme BP. 8,9 The clinical impact of BP-lowering drugs in the acute phase of stroke is also poorly understood. Calcium channel blockers (CCBs), ␤-blockers (BBs), and probably the angiotensin-converting enzyme (ACE) inhibitors, prostacyclin and nitric oxide each effectively reduce BP during the acute phase of stroke according to a Cochrane Database Systematic Review.…”