This is the first study to demonstrate that a diminished nocturnal decline in blood pressure is a risk factor for cardiovascular mortality, independent of the overall blood pressure load during a 24-h period, in the general population.

Home blood pressure measurement had a stronger predictive power for mortality than did screening blood pressure measurement for a general population. This appears to be the first study in which the prognostic significances of home and screening blood pressure measurements have been compared.

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Abstract-To investigate the association between cardiovascular mortality and short-term variabilities in blood pressure and heart rate, we performed a long-term prospective study of ambulatory blood pressure monitoring in Ohasama, Japan, starting in 1987. We obtained ambulatory blood pressure and heart rate in 1542 subjects Ն40 years of age. Blood pressure and heart rate variabilities were estimated as a standard deviation measured every 30 minutes by ambulatory monitoring. There were 67 cardiovascular deaths during the follow-up period (meanϭ8.5 years). The Cox proportional hazards model, adjusted for possible confounding factors, demonstrated a significant increase in cardiovascular mortality, with an increase in daytime systolic ambulatory blood pressure variability. A similar trend was observed in daytime diastolic and nighttime ambulatory blood pressures. Cardiovascular mortality rate increased linearly, with a decrease in daytime heart rate variability. Subjects in whom the daytime systolic ambulatory blood pressure variability was larger than third quintile and the daytime heart rate variability was lower than the meanϪSD were at extremely high risk of cardiovascular mortality. The blood pressure and heart rate variabilities obtained every 30 minutes by ambulatory blood pressure monitoring were independent predictors for cardiovascular mortality in the general population.

Abstract-In previous studies, of which several were underpowered, the relation between cardiovascular outcome and blood pressure (BP) variability was inconsistent. We followed health outcomes in 8938 subjects (mean age: 53.0 years; 46.8% women) randomly recruited from 11 populations. At baseline, we assessed BP variability from the SD and average real variability in 24-hour ambulatory BP recordings. We computed standardized hazard ratios (HRs) while stratifying by cohort and adjusting for 24-hour BP and other risk factors. Over 11.3 years (median), 1242 deaths (487 cardiovascular) occurred, and 1049, 577, 421, and 457 participants experienced a fatal or nonfatal cardiovascular, cardiac, or coronary event or a stroke.Higher diastolic average real variability in 24-hour ambulatory BP recordings predicted (PՅ0.03) total (HR: 1.14) and cardiovascular (HR: 1.21) mortality and all types of fatal combined with nonfatal end points (HR: Ն1.07) with the exception of cardiac and coronary events (HR: Յ1.02; PՆ0.58). Higher systolic average real variability in 24-hour ambulatory BP recordings predicted (PϽ0.05) total (HR: 1.11) and cardiovascular (HR: 1.16) mortality and all fatal combined with nonfatal end points (HR: Ն1.07), with the exception of cardiac and coronary events (HR: Յ1.03; PՆ0.54). SD predicted only total and cardiovascular mortality. While accounting for the 24-hour BP level, average real variability in 24-hour ambulatory BP recordings added Ͻ1% to the prediction of a cardiovascular event. Sensitivity analyses considering ethnicity, sex, age, previous cardiovascular disease, antihypertensive treatment, number of BP readings per recording, or the night:day BP ratio were confirmatory. In conclusion, in a large population cohort, which provided sufficient statistical power, BP variability assessed from 24-hour ambulatory recordings did not contribute much to risk stratification over and beyond 24-hour BP. (Hypertension. 2010;55:1049-1057.)Key Words: blood pressure variability Ⅲ ambulatory blood pressure Ⅲ population science Ⅲ risk factors Ⅲ epidemiology A mbulatory blood pressure monitoring not only provides information on the blood pressure level but on the diurnal changes in blood pressure as well. Blood pressure variability includes both short-term and circadian components, which can be estimated by the SD of the blood pressure values over a defined period of the day or by the night:day blood pressure ratio, respectively. We recently reported in Ͼ7000 subjects recruited from 6 populations on the prognos- Although the aforementioned analyses shed light on the association between outcome and long-term blood pressure variability, the predictive value of short-term reading-toreading blood pressure variability remains uncertain. Possible limitations of previous studies were a lack of statistical power, 2-5 selection of specific groups of patients, 5-7 categorization of variability by arbitrary cutoff points, 2,4,7-9 and sole reliance on fatal end points. 10,11 Moreover, various parameters can capture short-term b...