title: Blood pressure load does not add to ambulatory blood pressure level for cardiovascular risk stratification.
abstract: Experts proposed blood pressure (BP) load derived from 24-hour ambulatory BP recordings as a more accurate predictor of outcome than level, in particular in normotensive people. We analyzed 8711 subjects (mean age, 54.8 years; 47.0% women) randomly recruited from 10 populations. We expressed BP load as percentage (%) of systolic/diastolic readings ≥135/≥85 mm Hg and ≥120/≥70 mm Hg during day and night, respectively, or as the area under the BP curve (mm Hg×h) using the same ceiling values. During a period of 10.7 years (median), 1284 participants died and 1109 experienced a fatal or nonfatal cardiovascular end point. In multivariable-adjusted models, the risk of cardiovascular complications gradually increased across deciles of BP level and load (P<0.001), but BP load did not substantially refine risk prediction based on 24-hour systolic or diastolic BP level (generalized R(2) statistic ≤0.294%; net reclassification improvement ≤0.28%; integrated discrimination improvement ≤0.001%). Systolic/diastolic BP load of 40.0/42.3% or 91.8/73.6 mm Hg×h conferred a 10-year risk of a composite cardiovascular end point similar to a 24-hour systolic/diastolic BP of 130/80 mm Hg. In analyses dichotomized according to these thresholds, increased BP load did not refine risk prediction in the whole study population (R(2)≤0.051) or in untreated participants with 24-hour ambulatory normotension (R(2)≤0.034). In conclusion, BP load does not improve risk stratification based on 24-hour BP level. This also applies to subjects with normal 24-hour BP for whom BP load was proposed to be particularly useful in risk stratification.
authors.affiliation: Studies Coordinating Centre, Research Unit Hypertension and Cardiovascular Epidemiology, KU Leuven Department of Cardiovascular Sciences, University of Leuven, Campus Sint Rafaël, Kapucijnenvoer 35, block D, Box 7001, BE-3000 Leuven, Belgium. jan.staessen@med.kuleuven.be or ja.staessen@maastrichtuniversity.nl.
authors.forename: Yan
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authors.lastname: Ohkubo
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authors.lastname: Jeppesen
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authors.lastname: Kuznetsova
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authors.initials: K
authors.lastname: Stolarz-Skrzypek
authors.forename: Valérie
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authors.lastname: Tikhonoff
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authors.lastname: Malyutina
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authors.lastname: Casiglia
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authors.lastname: Nikitin
authors.forename: Lars
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authors.forename: Edgardo
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authors.lastname: Sandoya
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authors.lastname: Kawecka-Jaszcz
authors.forename: Jan
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authors.lastname: Filipovsky
authors.forename: Yutaka
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authors.lastname: Imai
authors.forename: Hans
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authors.lastname: Ibsen
authors.forename: Eoin
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authors.lastname: O'Brien
authors.forename: Jiguang
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authors.lastname: Wang
authors.forename: Jan A
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authors.lastname: Staessen
mesh_terms: D000328:Adult; D000368:Aged; D019540:Area Under Curve; D001794:Blood Pressure / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory; D002318:Cardiovascular Diseases / Q000453:epidemiology*; D002940:Circadian Rhythm / Q000502:physiology; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications* / Q000503:physiopathology*; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012189:Retrospective Studies; D012307:Risk Factors
keywords: ambulatory blood pressure monitoring; epidemiology; risk factors