Reproducibility of blood pressure dipping: Relation to day-to-day variability in sleep quality

• Type of Material: Article
• Authors: Alan L. Hinderliter, University of North Carolina; Faye Routledge, Emory University; James A. Blumenthal, Duke University; Gary Koch, University of North Carolina; Michael A. Hussey, University of North Carolina; William K. Wohlgemuth, Miami VA Healthcare System; Andrew Sherwood, Duke University
• Language: English
• Date: 2013-11-01
• Publisher: Elsevier: 12 months
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2013 American Society of Hypertension. All rights reserved.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.jash.2013.06.001
• Title of Journal or Parent Work: Journal of the American Society of Hypertension
• ISSN: 1933-1711
• Volume: 7
• Issue: 6
• Start Page: 432
• End Page: 439
• Grant/Funding Information: This study was supported by Grant HL072390 from the National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, and grant M01-RR-30 from the General Clinical Research Center program, National Center for Research Resources, National Institutes of Health.
• Keywords: fragmentation index; Life Sciences & Biomedicine; POPULATION; PREDICTING MORTALITY; Science & Technology; PATTERN; NOCTURNAL DECLINE; Peripheral Vascular Disease; RISK; LONG-TERM; Cardiovascular System & Cardiology; ISOLATED SYSTOLIC HYPERTENSION; 24-H; Ambulatory blood pressure monitoring; actigraphy; VALIDATION; PROGNOSTIC VALUE
• Research Categories: Health Sciences, Medicine and Surgery

Abstract

Previous studies of the reproducibility of blood pressure (BP) dipping have yielded inconsistent results. Few have examined factors that may influence day-to-day differences in dipping. Ambulatory BP monitoring was performed on three occasions, approximately 1 week apart, in 115 untreated adult subjects with elevated clinic BPs. The mean ± standard deviation BP dip was 18 ± 7/15 ± 5 mm Hg (sleep/awake BP ratio = 0.87 ± 0.05/0.82 ± 0.06), with a median (interquartile range) day-to-day variation of 5.2 (3.1-8.1)/4.3 (2.8-5.6) mm Hg. There was no decrease in variability with successive measurements. The reproducibility coefficient (5.6 [95% confidence interval, 5.1-6.1] mm Hg) was greater and the intraclass correlation coefficient (0.53 [95% confidence interval, 0.42-0.63]) was smaller for the systolic dip than for 24-hour or awake systolic BPs, suggesting greater day-to-day variability in dipping. Variability in systolic dipping was greater in subjects with higher awake BP, but was not related to age, gender, race, or body mass index. Within individuals, day-to-day variations in dipping were related to variations in the fragmentation index (P <.001), a measure of sleep quality. Although mean 24-hour and awake BPs were relatively stable over repeated monitoring days, our study confirms substantial variability in BP dipping. Day-to-day differences in dipping are related to sleep quality.