Reproducibility and Clinical Implications of Masked Hypertension Hypertension-the most important cardiovascular disease (CVD) risk factor-can go undetected for one of two main reasons: either a person's blood pressure (BP) is simply not checked (i.e., the person is not screened), or the screening measurement itself does not detect it. Over the past four decades, much effort has been devoted to improving screening rates for detection of high BP. Only recently, however, through the use of 24-hour ambulatory BP monitoring (ABPM), has attention been given to the possibility that "false negative" office BP measurements may be substantial in number and clinically important. Masked hypertension (MH) denotes BP that is not elevated (<140/90 mm Hg) when measured in the office, but elevated when repeated measurements are averaged over the course of a day. The prevalence of MH in the general adult population is estimated to be 10%. Recent data suggest that people with MH have cardiovascular target organ damage and an increase in CVD events of an order of magnitude approaching that seen in people with sustained hypertension (elevated office BP levels with elevated out-of-office BP levels). Many important unresolved questions need to be answered, however, before clinical recommendations can be made. Chief among these is whether MH represents a reproducible phenomenon. Another important consideration is clarifying whether home BP monitoring (HBPM) can be used in place of ABPM to identify MH, and if so, whether it serves to identify the same at-risk population.
We aim to (1) assess the reproducibility of MH and evaluate the agreement between HBPM and ABPM in identifying MH, (2) identify demographic, psychosocial, and clinical factors associated with MH, and (3) explore the degree of target organ damage and subclinical atherosclerosis associated with MH. To accomplish these aims, we will perform two sets of office, ABPM, and HBPM BP measurements one week apart on 420 adults not under treatment for hypertension recruited from twelve primary care practices. Other measures will include serum glucose, lipids, and C-reactive protein;urine albumin;left ventricular mass index;coronary artery calcium;perceived stress;job and home strain;and trait-anger. The research team has extensive experience with BP measurement research, psychosocial effects on BP, cardiac imaging methods, coronary heart disease risk assessment, and conducting research in networks of primary care practices. Our study is expected to improve our understanding of the epidemiology and implications of MH and ultimately lead to strategies that will improve detection of high BP in the population.

Public Health Relevance

The possibility that office blood pressure measurements fail to detect hypertension for millions of people demands the kind of rigorous investigations described in the proposed study. The findings are expected to lead to clinical strategies enabling greater recognition of hypertension, and therefore, ultimately to a reduction in cardiovascular morbidity and mortality in the population.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL098604-03
Application #
8305173
Study Section
Clinical and Integrative Cardiovascular Sciences Study Section (CICS)
Program Officer
Einhorn, Paula
Project Start
2010-06-01
Project End
2014-05-31
Budget Start
2012-06-01
Budget End
2014-05-31
Support Year
3
Fiscal Year
2012
Total Cost
$707,599
Indirect Cost
$283,569
Name
University of North Carolina Chapel Hill
Department
Family Medicine
Type
Schools of Medicine
DUNS #
608195277
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Viera, Anthony J; Lin, Feng-Chang; Tuttle, Laura A et al. (2015) Levels of office blood pressure and their operating characteristics for detecting masked hypertension based on ambulatory blood pressure monitoring. Am J Hypertens 28:42-9
Viera, Anthony J; Lin, Feng-Chang; Tuttle, Laura A et al. (2014) Reproducibility of masked hypertension among adults 30 years or older. Blood Press Monit 19:208-15
Peacock, J; Diaz, K M; Viera, A J et al. (2014) Unmasking masked hypertension: prevalence, clinical implications, diagnosis, correlates and future directions. J Hum Hypertens 28:521-8
Viera, Anthony J; Shimbo, Daichi (2014) Ambulatory blood pressure phenotypes and the risk for hypertension. Curr Hypertens Rep 16:481
Asher, Gary N; Viera, Anthony J; Weaver, Mark A et al. (2012) Effect of hawthorn standardized extract on flow mediated dilation in prehypertensive and mildly hypertensive adults: a randomized, controlled cross-over trial. BMC Complement Altern Med 12:26
Viera, Anthony J; Lin, Feng-Chang; Hinderliter, Alan L et al. (2012) Nighttime blood pressure dipping in young adults and coronary artery calcium 10-15 years later: the coronary artery risk development in young adults study. Hypertension 59:1157-63