| Time-weighted vs. conventional quantification of 24-h average systolic and diastolic ambulatory blood pressures. | |
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MedLine Citation:
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PMID: 20125038 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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BACKGROUND: Conventional calculation of mean 24-h ambulatory blood pressure (BP), SBP and DBP based on the average of all BP readings disregards the fact that a larger number of measurements is usually scheduled during the daytime than at night, an imbalance possibly leading to an overestimation of 24-h average BP. The aim of our study was to quantify this possible bias and to explore its determinants. METHODS: Four hundred and fifty untreated individuals were subdivided into three groups (150 individuals each) with three different ambulatory blood pressure measurement schedules for day/night: group I, four (day)/two (night) readings/h; group II, four (day)/three (night) readings/h; and group III, with BP readings every 30 min throughout 24 h. Hourly and 24-h averages were computed. The conventional 24-h averages of all SBP and DBP values were compared with the averages of hourly SBP and DBP mean values (time-weighted quantification). The difference between 24-h conventional and 24-h time-weighted BP was computed in each group and related to the degree of nocturnal BP dip and to the ratio between the number of readings of day and night. RESULT: In the three groups, 24-h conventional and 24-h time-weighted BP values were highly correlated (r > 0.99), 24-h conventional SBP and DBP being significantly higher (P < 0.01) than the corresponding 24-h time-weighted values in groups I and II but not in group III (Bland-Altman analysis). The bias magnitude was related to the day/night ratio in number of readings and to nocturnal BP dip in groups I and II (P < 0.01) but not in group III. CONCLUSION: The higher number of readings/h during daytime leads to an overestimation of conventional 24-h average BP, particularly in individuals with preserved nocturnal BP dipping. This can be avoided either by scheduling the same number of readings/h throughout 24 h or by performing a time-weighted quantification of 24-h BP. The clinical implications of these different approaches deserve further investigation. |
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Authors:
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Jos? A Octavio; Jes?s Contreras; Pablo Amair; Bernardo Octavio; Domenico Fabiano; Federico Moleiro; Stefano Omboni; Antonella Groppelli; Grzegorz Bilo; Giuseppe Mancia; Gianfranco Parati |
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Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: Journal of hypertension Volume: 28 ISSN: 1473-5598 ISO Abbreviation: J. Hypertens. Publication Date: 2010 Mar |
Date Detail:
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Created Date: 2010-02-17 Completed Date: 2010-06-01 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8306882 Medline TA: J Hypertens Country: England |
Other Details:
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Languages: eng Pagination: 459-64 Citation Subset: IM |
Affiliation:
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Experimental Cardiology, Tropical Medicine Institute, Central University, Caracas, Venezuela. |
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| MeSH Terms | |
Descriptor/Qualifier:
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Blood Pressure* Blood Pressure Monitoring, Ambulatory / methods* Circadian Rhythm* Diastole Humans Systole |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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