Reliability of Office, Home, and Ambulatory Blood Pressure Measurements and Correlation With Left Ventricular Mass.

BACKGROUND: Determining the reliability and predictive validity of office blood pressure (OBP), ambulatory BP (ABP), and home BP (HBP) can inform which is best for diagnosing hypertension and estimating risk of cardiovascular disease. OBJECTIVES: This study aimed to assess the reliability of OBP, HBP, and ABP and evaluate their associations with left ventricular mass index (LVMI) in untreated persons. METHODS: The Improving the Detection of Hypertension (IDH) study, a community-based observational study, enrolled 408 participants who had OBP assessed at 3 visits, and completed 3 weeks of HBP, 2 24-h ABP recordings, and a 2-dimensional echocardiogram. Mean age was 41.2 ± 13.1 years, 59.5% were women, 25.5% African American, and 64.0% Hispanic. RESULTS: The reliability of 1 week of HBP, 3 office visits with mercury sphygmomanometry, and 24-h ABP were 0.938, 0.894, and 0.846 for systolic and 0.918, 0.847, and 0.843 for diastolic BP, respectively. The correlations among OBP, HBP, and ABP, corrected for regression dilution bias, were 0.74 to 0.89. After multivariable adjustment including OBP and 24-h ABP, 10 mm Hg higher systolic and diastolic HBP were associated with 5.07 (standard error [SE]: 1.48) and 3.92 (SE: 2.14) g/m2 higher LVMI, respectively. After adjustment for HBP, neither systolic or diastolic OBP nor ABP was associated with LVMI. CONCLUSIONS: OBP, HBP, and ABP assess somewhat distinct parameters. Compared with OBP (3 visits) or 24-h ABP, systolic and diastolic HBP (1 week) were more reliable and more strongly associated with LVMI. These data suggest that 1 week of HBP monitoring may be the best approach for diagnosing hypertension.

Stress management in the workplace for employees with hypertension: a randomized controlled trial.

While behavioral interventions can improve blood pressure (BP) in individuals with hypertension, getting such services to people who could benefit remains difficult. Workplace programs have potential as dissemination vehicles. The objective is to evaluate the effectiveness of a standardized stress management program delivered in groups at the workplace for reducing BP compared with enhanced usual care. This randomized controlled trial studied 92 urban medical center employees with hypertension randomized into two groups. The intervention was a 10-week group workshop on cognitive-behavioral coping skills. Enhanced usual care included self-help materials for BP reduction and physician referral. Intervention group participants' systolic BP (SBP) decreased 7.5 mm Hg over controls between baseline and follow-up, from 149.1 (95% CI: 146.0-152.1) to 140.0 (95% CI: 134.7-145.2), p < .001. The differential change between intervention and enhanced usual care groups (Group × Time interaction) was 7.5 mm Hg (t = -2.05; p = .04). Diastolic BP reductions were not significantly different. Scores on measures of emotional exhaustion and depressive rumination showed significant improvements and correlated with reductions in SBP. There was no significant change in the usual care group. A standardized worksite group intervention produced clinically meaningful reductions in SBP in participants with hypertension.

Clinic Blood Pressure Underestimates Ambulatory Blood Pressure in an Untreated Employer-Based US Population: Results From the Masked Hypertension Study.

BACKGROUND: Ambulatory blood pressure (ABP) is consistently superior to clinic blood pressure (CBP) as a predictor of cardiovascular morbidity and mortality risk. A common perception is that ABP is usually lower than CBP. The relationship of the CBP minus ABP difference to age has not been examined in the United States. METHODS: Between 2005 and 2012, 888 healthy, employed, middle-aged (mean±SD age, 45±10.4 years) individuals (59% female, 7.4% black, 12% Hispanic) with screening BP <160/105 mm Hg and not taking antihypertensive medication completed 3 separate clinic BP assessments and a 24-hour ABP recording for the Masked Hypertension Study. The distributions of CBP, mean awake ABP (aABP), and the CBP-aABP difference in the full sample and by demographic characteristics were compared. Locally weighted scatterplot smoothing was used to model the relationship of the BP measures to age and body mass index. The prevalence of discrepancies in ABP- versus CBP-defined hypertension status-white-coat hypertension and masked hypertension-were also examined. RESULTS: Average systolic/diastolic aABP (123.0/77.4±10.3/7.4 mm Hg) was significantly higher than the average of 9 CBP readings over 3 visits (116.0/75.4±11.6/7.7 mm Hg). aABP exceeded CBP by >10 mm Hg much more frequently than CBP exceeded aABP. The difference (aABP>CBP) was most pronounced in young adults and those with normal body mass index. The systolic difference progressively diminished, but did not disappear, at older ages and higher body mass indexes. The diastolic difference vanished around age 65 and reversed (CBP>aABP) for body mass index >32.5 kg/m2. Whereas 5.3% of participants were hypertensive by CBP, 19.2% were hypertensive by aABP; 15.7% of those with nonelevated CBP had masked hypertension. CONCLUSIONS: Contrary to a widely held belief, based primarily on cohort studies of patients with elevated CBP, ABP is not usually lower than CBP, at least not among healthy, employed individuals. Furthermore, a substantial proportion of otherwise healthy individuals with nonelevated CBP have masked hypertension. Demonstrated CBP-aABP gradients, if confirmed in representative samples (eg, NHANES [National Health and Nutrition Examination Survey]), could provide guidance for primary care physicians as to when, for a given CBP, 24-hour ABP would be useful to identify or rule out masked hypertension.

Correlates of isolated nocturnal hypertension and target organ damage in a population-based cohort of African Americans: the Jackson Heart Study.

BACKGROUND: African Americans have higher rates of nocturnal hypertension and less nocturnal blood pressure (BP) dipping compared with whites. Although nocturnal hypertension is associated with increased cardiovascular morbidity and mortality, its clinical significance among those with normal daytime BP is unclear. This paper reports the prevalence and correlates of isolated nocturnal hypertension (INH) in a population-based cohort of African Americans enrolled in the Jackson Heart Study (JHS). METHODS: The study sample included 425 untreated, normotensive and hypertensive JHS participants who underwent 24-hour ambulatory BP monitoring (ABPM), echocardiography, and 24-hour urine collection. Multiple logistic regression and 1-way analysis of variance models were used to test the hypothesis that those with INH have worse target organ damage reflected by greater left ventricular (LV) mass and proteinuria compared with normotensive participants. RESULTS: Based on 24-hour ABP profiles, 19.1% of participants had INH. In age and sex-adjusted models, participants with INH had greater LV mass compared with those who were normotensive (P = 0.02), as well as about 3 times the odds of LV hypertrophy and proteinuria (Ps < 0.10). However, multivariable adjustment reduced the magnitude and statistical significance of each of these differences. CONCLUSIONS: INH was associated with increased LV mass compared with normo tension in a population-based cohort of African Americans enrolled in the JHS. There were trends toward a greater likelihood of LV hyper trophy and proteinuria among participants with INH vs. those who were normotensive. The clinical significance of the noted target organ damage should be explored in this population.

A novel and simple protocol for the validation of home blood pressure monitors in clinical practice.

BACKGROUNDS: Although the European Society of Hypertension International Protocol for the validation of blood pressure (BP) measuring devices has simplified the validation protocol, it is still not feasible for use in routine clinical practice. OBJECTIVES: We sought to devise a method for validating individual home blood pressure (HBP) monitors that is simple enough for use in routine clinical practice. METHODS: We consecutively enrolled 92 hypertensive patients (mean age: 63.2 ± 14.6 years) from the hypertension clinic at the Columbia University Medical Center. Five sequential same-arm BP readings were recorded by a physician: first (D1), second (D2), and fourth (D3) using an HBP device; the third (M1) and fifth (M2) readings were taken manually using a mercury sphygmomanometer. Analyses focused on the absolute values of the differences in the BP values. In step 1, differences D2-M1, M1-D3, and D3-M2 were calculated and if two of three BP differences were within 5 mmHg (or 10 mmHg), the monitor 'passed'. When a monitor failed step 1, if either the difference between M1 and the average of D2 and D3, or the difference between D3 and the average of M1 and M2 was within 5 mmHg (or 10 mmHg), it was judged to have 'passed'. RESULTS: We used only systolic blood pressure to simplify the protocol. In step 1, the number of monitors in which two of three BP differences were within 5 mmHg was 43 (46.7%) and those within 10 mmHg was 73 (79.4%) of 92 total monitors. Of those that failed the 5 mmHg criterion of step 1 (N = 49), 20 passed step 2. Therefore, a total of 63 monitors (68.5%) fulfilled the 5 mmHg criteria. Of 19 monitors that failed step 1 using the 10 mmHg criterion, 12 fulfilled the 10 mmHg criterion for step 2, resulting in 85 of the 92 (92.4%) monitors passing the test. CONCLUSION: This simplified validation protocol may be of value for the routine evaluation of HBP monitors in clinical practice.

Automatic office blood pressure measured without doctors or nurses present.

BACKGROUND: We evaluated the agreement between office blood pressure (OBP) measured by a mercury sphygmomanometer (Sphyg) and an automatic (Auto) device without any observers, and compared Auto and Sphyg OBP with ambulatory blood pressure (ABP) and home blood pressure (HBP). METHODS: OBP was measured in 75 hypertensive patients at two sites using an automatic monitor without a doctor or a nurse present and by Sphyg during three clinic visits. Between visits, monitoring of ABP and HBP was also performed. RESULTS: The mean Auto OBP was similar to that of Sphyg OBP and the values were closely correlated (intraclass correlation coefficient=0.84 for systolic OBP and 0.91 for diastolic OBP); however, the difference between Auto and Sphyg systolic OBP (1.6 ± 8.2 mmHg) varied by the first office visit, sex, and the site. Auto systolic OBP was lower than both systolic awake ABP (137.1 ± 14.7 mmHg) and HBP (139.2 ± 15.6 mmHg). Auto systolic OBP and Sphyg OBP were similarly correlated with systolic awake ABP (both r=0.59, P<0.001). The mean Auto diastolic OBP was similar to that of Sphyg OBP (81.1 ± 11.3 vs. 80.3 ± 13.3 mmHg, P=0.20, intraclass correlation coefficient=0.91), and diastolic awake ABP and HBP. Auto diastolic OBP and Sphyg OBP were related to diastolic awake ABP (both r>0.68, P<0.001). In multivariable analyses, neither OBP measure was a significantly stronger predictor of out-of-office blood pressure than the other. CONCLUSION: Auto systolic OBP measured without a doctor or a nurse present was lower than systolic awake ABP and HBP. Auto and rigorously assessed Sphyg OBP had similar means and were similarly related to awake ABP. Auto OBP might be an advantageous alternative to Sphyg measurements in the usual clinic setting.

Race differences in the physical and psychological impact of hypertension labeling.

BACKGROUND: Blood pressure screening is an important component of cardiovascular disease prevention, but a hypertension diagnosis (i.e., label) can have unintended negative effects on patients' well-being. Despite persistent disparities in hypertension prevalence and outcomes, whether the impact of labeling differs by race is unknown. The purpose of this study was to evaluate possible race differences in the relationship between hypertension labeling and health-related quality of life and depression. METHODS: The sample included 308 normotensive and unmedicated hypertensive subjects from the Neighborhood Study of Blood Pressure and Sleep, a cross-sectional study conducted between 1999 and 2003. Labeled hypertension was defined (by self-report) as having been diagnosed with high blood pressure or prescribed antihypertensive medications. Effects of labeling and race on self-reported physical and mental health and depressive symptoms were tested using multivariate analysis of covariance, controlling for age, sex, body mass index (BMI), previous medication use, and "true" hypertension status, defined by average daytime ambulatory blood pressure (ABP). RESULTS: Both black and white subjects who had been labeled as hypertensive reported similarly poorer physical health than unlabeled subjects (P = 0.001). However, labeling was associated with poorer mental health and greater depressive symptoms only among blacks (Ps < 0.05 for the interactions). These findings were not explained by differences in socioeconomic status. CONCLUSIONS: These results are consistent with previous studies showing negative effects of hypertension labeling, and demonstrate important race differences in these effects. Clinical approaches to communicating diagnostic information that avoid negative effects on well-being are needed, and may require tailoring to patient characteristics such as race.

Can blood pressure measurements taken in the physician's office avoid the 'white coat' bias?

OBJECTIVE: Obtaining an accurate blood pressure (BP) reading is vital for diagnosing hypertension. However, BP measures taken in the physician's clinic (CBP) are subject to the 'white coat' bias. Measurements taken outside the office using ambulatory (ABP) and home (HBP) monitoring are superior predictors of cardiovascular diseases compared with CBP, but ABP remains underutilized because of the effort and expense involved. Unfortunately, HBP has limitations, including questionable device validity and patient compliance. Thus, it is important to identify feasible alternative techniques to measure BP in the office that will increase the accuracy of the diagnosis. METHODS: Auscultatory BP was measured in 249 patients in a nonclinical setting by trained technicians (NCBP); on the following day, patients were taken to their physician (CBP). They were also given an HBP monitor, and a 36 h ABP monitoring. Because ABP is considered the gold standard for prediction of cardiovascular disease, these readings were used as the criterion in a statistical model in which CBP, HBP, and NCBP were entered as predictors. The level of agreement between measurements was estimated. RESULTS: Multiple regression analysis showed that HBP and NCBP (P < 0.001) explained 94 and 87% of the variance in systolic and diastolic ABP, respectively. The agreement between NCBP and ABP was greater than that between CBP and ABP or between HBP. CONCLUSION: When ABP monitoring and HBP monitoring are not options, the NCBP at the clinic can avoid the white coat bias and therefore improve diagnosis.

Age and the difference between awake ambulatory blood pressure and office blood pressure: a meta-analysis.

BACKGROUND: Ambulatory blood pressure (BP) (ABP) is a better predictor of adverse cardiovascular events than office BP (OBP). Owing to the extensive literature on the 'white coat effect', it is widely believed that ABP tends to be lower than OBP, with statements to this effect in Joint National Committee VII. However, recent evidence suggests that the difference varies systematically with age. METHODS: We searched PubMed to identify population studies, published before April 2009, which assessed OBP and either ABP or home BP (HBP). On account of significant heterogeneity in the outcomes, random effect models were used for the meta-analyses. RESULTS: OBP increased with age more steeply than awake ABP. OBP became higher than awake systolic/diastolic ABP at the age of 51.3/42.7 years in men (13 studies, N=3562) and 51.9/42.3 years in women (11 studies, N=2585). In the data in which OBP and HBP were measured (eight studies, N=4916), OBP was higher than HBP at all ages. In the data in which OBP, awake ABP, and HBP were all measured (two studies, N=895), awake ABP was higher than HBP at younger ages, becoming similar at the older age. CONCLUSION: OBP tends to be higher than awake ABP only after the age of 50 years for systolic and after the age of 45 years for diastolic BP, but is lower than ABP at younger ages; in contrast OBP tends to exceed HBP at all ages.

Correlations between different measures of clinic, home, and ambulatory blood pressure in hypertensive patients.

OBJECTIVES: It is not well known how clinic, home, and ambulatory measures of blood pressure (BP) correlate with each other. We performed this study to clarify the level of agreement among these different BP measures. MATERIALS AND METHODS: We enrolled 56 hypertensive patients (mean age: 60 ± 14 years; 54% were females). The study consisted of three clinic visits, self-monitoring of home BP between visits, and ambulatory blood pressure (ABP) monitoring at the second visit. Patients were given a home BP monitor programmed to automatically take three consecutive readings at fixed intervals of 1 min. The associations between clinic BP (mercury sphygmomanometer and HEM-5001), home BP (the average of morning and evening, second and third BP readings), and average awake ABP were compared using the intraclass correlation for agreement and Bland-Altman plots. RESULTS: The averages of clinic sphygmomanometer, clinic HEM-5001, awake ABP, and home BP were 129 of 77, 131 of 76, 131 of 79, and 133 of 77 mmHg, respectively. Clinic BP by HEM-5001 was strongly correlated with that of mercury sphygmomanometer. Home systolic blood pressure was moderately correlated with awake ABP, but mercury diastolic blood pressure (DBP) was more closely correlated with awake DBP than home DBP. CONCLUSION: Clinic BP measured with the automated monitor could be used as an alternative for the evaluation of BP in the office. Under rigorously standardized conditions, clinic and home BP could be used as an alternative to awake ABP.

Explaining gender differences in the white coat effect.

OBJECTIVES: To discern whether gender was a unique predictor of the white coat effect (WCE) in a population of normotensives and patients diagnosed with hypertension. METHODS: Participants (n=252) underwent a doctor's office visit to have their blood pressure measured. Multiple blood pressure readings were taken by both a research assistant and by the attending physician. In addition, measures of anxiety variables were collected during the visit. Participants then underwent a 36-h ambulatory blood pressure monitoring. RESULTS: Gender was a significant predictor of the systolic WCE, but, as expected, the effect size was small and was no longer significant when age and BMI were included in the regression model. State anxiety emerged as a significant independent predictor of systolic WCE; however, when household income was included in the model it became the only significant independent predictor (ß=0.203, P<0.05), in addition to gender, age, and BMI. CONCLUSION: This study suggests that the association between gender and the systolic WCE is small, and likely accounted for by other variables including age, BMI, state anxiety, and household income. Thus, gender may be of limited use in helping identify patients who may be more likely to have WCE or white coat hypertension. Gender differences in this area should be interpreted with great caution.

Masked hypertension defined by ambulatory blood pressure monitoring is associated with an increased serum glucose level and urinary albumin-creatinine ratio.

The authors evaluated the relationship of hypertensive target organ damage to masked hypertension assessed by ambulatory blood pressure (BP) and home blood pressure (HBP) monitoring in 129 participants without taking antihypertensive medication. Masked hypertension was defined as office BP < or =140/90 mm Hg and 24-hour ambulatory BP > or =130/80 mm Hg. The masked hypertensive participants defined by 24-hour ambulatory BP (n=13) had a higher serum glucose level (126 vs 96 mg/dL, P=.001) and urinary albumin-creatinine ratio (38.0 vs 7.5 mg/gCr, P<.001) than the normotensive participants (n=74); however, these relationships were not observed when the authors defined groups using HBP (> or =135/85 mm Hg). Masked hypertension by both 24-hour ambulatory BP and HBP had a higher urinary albumin-creatinine ratio than normotension by both 24-hour ambulatory BP and HBP (62.1 vs 7.4 mg/gCr, P=.001), and than masked hypertension by HBP alone (9.3 mg/gCr, P=.009). Masked hypertension defined by 24-hour ambulatory BP is associated with an increased serum glucose level and urinary albumin-creatinine ratio, but these relationships are not observed in masked hypertension defined by HBP.

Prehypertension and the risk for cardiovascular disease in the Japanese general population: the Jichi Medical School Cohort Study.

BACKGROUND: Prehypertension is associated with an increased risk of the development of hypertension and subsequent cardiovascular disease. However, it is unclear whether the increased risk of cardiovascular disease associated with prehypertension varies by duration of follow-up (i.e., the first 5 years vs. second 5 years) or varies between nonelderly and elderly individuals. METHODS: We enrolled 11,000 community dwelling persons (6739 women and 4261 men, aged 18-90 years) from the Japanese general population, followed them for an average of 10.7 +/- 2.4 years (117,517 person-years) and evaluated the incidence of cardiovascular events (including both stroke and myocardial infarction). RESULTS: In the full cohort, prehypertension was associated with a 45% higher risk of cardiovascular events than normal blood pressure after adjusting for traditional cardiovascular risk factors (hazard ratio = 1.45, P = 0.03). The risk of cardiovascular events with prehypertension during the second 5-year period was elevated in the nonelderly subgroup (<65 years) (hazard ratio = 2.13, P = 0.01), but not in the elderly subgroup (>or=65 years) (hazard ratio = 0.93, P = 0.82) (P = 0.054 for the difference in hazard ratio). The elevated risk with prehypertension during the first 5-year period was not significant in either the nonelderly (hazard ratio = 1.60, P = 0.36) or elderly (hazard ratio = 1.19, P = 0.63) group. However, the risks with prehypertension were not statistically different between the first and second 5-year period. CONCLUSION: Prehypertension is associated with an increased 10-year risk of cardiovascular disease; the provocative finding that this risk may be especially elevated during the second 5-year period in the nonelderly requires confirmation in a larger cohort.

Increased heart rate variability during sleep is a predictor for future cardiovascular events in patients with type 2 diabetes.

We aimed this study to test the hypotheses that heart rate (HR) variability, evaluated by ambulatory blood pressure monitoring (ABPM), predicts risk of incident cardiovascular disease (CVD) in patients with type 2 diabetes (T2DM). ABPM was performed in 200 normotensive or hypertensive subjects with T2DM and 257 hypertensive subjects without diabetes (the mean age: 66.9+/-9.2 years; 38% were male). All subjects were untreated at the time of ABPM, and were followed for 67+/-27 months. Various measures of HR variability-standard deviation (s.d.) of HR, the root-mean-square of successive differences (RMSSD) of HR, systolic blood pressure (SBP)-HR relationships evaluated by slope and coefficients of correlation between SBP and HR-were used for the analyses. Cox proportional hazard models were used to estimate hazard ratios and 95% confidence intervals, after controlling for age, sex, body mass index, serum creatinine and 24-h SBP. During follow-up, there were 34 cardiovascular events. Awake HR variability in diabetics was smaller than non-diabetics, but sleep HR variability was similar between the groups. In multivariable analyses, increased sleep HR variability evaluated by s.d. and RMSSD of sleep HR, and slope and correlation coefficient of SBP-HR each was independently associated with the increased risk of CVD in T2DM. For non-diabetics, decreased slope of 24 h SBP-HR, and decreased correlation of 24 h SBP-HR were associated with increased risk of CVD. In conclusion, increased HR variability during sleep was a predictor for incident CVD in T2DM, but not in non-diabetics. Increased HR variability at night would reflect pathophysiological mechanism of T2DM.

When and how to use self (home) and ambulatory blood pressure monitoring.

This American Society of Hypertension position paper focuses on the importance of out-of-office blood pressure (BP) measurement for the clinical management of patients with hypertension and its complications. Studies have supported direct and independent associations of cardiovascular risk with ambulatory BP and inverse associations with the degree of BP reduction from day to night. Self-monitoring of the BP (or home BP monitoring) also has advantages in evaluating patients with hypertension, especially those already on drug treatment, but less is known about its relation to future cardiovascular events. Data derived from ambulatory BP monitoring (ABPM) allow the identification of high-risk patients, independent from the BP obtained in the clinic or office setting. While neither ABPM nor self-BP monitoring are mandatory for the routine diagnosis of hypertension, these modalities can enhance the ability for identification of white-coat and masked hypertension and evaluate the extent of BP control in patients on drug therapy.

Insomnia and sleep duration as mediators of the relationship between depression and hypertension incidence.

BACKGROUND: Depression has been found to predict the incidence of hypertension and other adverse cardiovascular events in prospective studies. Insomnia and short sleep duration, which are typical symptoms of depression, have also been shown to increase the risk for hypertension incidence. Insomnia is associated with increased activation of the hypothalamic-pituitary-adrenal axis, and short sleep duration raises average 24-h blood pressure, which over time could lead to structural adaptations that gradually reset the entire cardiovascular system to operate at an elevated pressure equilibrium. No previous published population studies have examined whether insomnia and sleep duration mediate the relationship between depression and hypertension incidence. METHODS: We conducted multivariate longitudinal (1982-1992) analyses stratified by age of the First National Health and Nutrition Examination Survey (NHANES I) (n = 4,913) using Cox proportional hazards models. RESULTS: Middle-aged subjects who suffered from depression at baseline were 44% more likely to be diagnosed with hypertension over the follow-up period after controlling for covariates (hazard ratio (HR) = 1.44, 95% confidence interval (CI) 1.15-1.80). Both short sleep duration and insomnia were also significantly associated with hypertension incidence. Consistent with insomnia and sleep duration acting as mediators of the relationship between depression and hypertension incidence, the inclusion of these variables in the multivariate models appreciably attenuated the association (HR = 1.27, 95% CI 1.00-1.61). Depression, sleep duration, and insomnia were not significantly associated with hypertension incidence in elderly subjects. CONCLUSIONS: These results suggest the hypothesis that treatment of sleep problems in middle-aged individuals suffering from depression could reduce their risk for developing hypertension, and its vascular and cardiac complications.

Prevalence and determinants of isolated systolic hypertension among young adults: the 1999-2004 US National Health And Nutrition Examination Survey.

BACKGROUND: Little is known about isolated systolic hypertension (ISH) in younger adults. We examined the prevalence and determinants of ISH in this age group using the 1999-2004 National Health and Nutrition Examination Surveys (NHANES) and made comparisons using data from NHANES III (1988-1994). METHODS: A total of 5685 adults aged 18-39 years and not on antihypertensive medications were analyzed. Prevalence estimates of ISH and potential risk factors were estimated by age and sex. For comparison of prevalence estimates with published reports of NHANES III data, age cutoffs (18-24, 25-34, and 35-44 year) by sex were also employed. A multivariate logistic regression model tested independent determinants of ISH. RESULTS: ISH in young adults had a higher prevalence than systolic/diastolic hypertension (1.57 +/- 0.23% vs. 0.93 +/- 0.18%). ISH prevalence increased within the last decade particularly for men for each respective age category [men (0.8 vs. 2.2%, 1.3 vs. 2.4%, 1.3 vs. 2.4%), women (0.0 vs. 0.3%, 0.1 vs. 0.7%, 1.7 vs. 1.8%)]. On multivariate analysis, obesity [odds ratio (OR): 2.68, 95% confidence interval (CI): 1.06, 6.77], male sex (OR: 2.19, 95% CI: 1.10, 4.37), education level less than high school (OR: 2.98, 95% CI: 1.10, 8.06), and current smoking (OR: 2.06, 95% CI: 1.03, 4.11) were characteristics independently associated with higher odds of ISH among young adults. Relative increases in prevalence between the surveys were noted for current smoking (24.3 vs. 51.5%), obesity (33.9 vs. 42.7%) and low educational level (18.4 vs. 38.6%). CONCLUSION: ISH among young adults is increasing in prevalence, and is more common than systolic/diastolic hypertension. Obesity, smoking, and low socioeconomic status appear to be important determinants of ISH among young adults and have all increased over the last decade.

Nocturnal nondipping of heart rate predicts cardiovascular events in hypertensive patients.

OBJECTIVE: It has not been established whether nocturnal nondipping of heart rate (HR) predicts future cardiovascular disease (CVD). We performed this study to test the hypothesis that nocturnal nondipping of HR predicts the risk of incident CVD independent of nocturnal blood pressure dipping pattern. METHODS: Ambulatory blood pressure monitoring was performed in 457 uncomplicated patients, who were being treated or evaluated for hypertension. They were followed for an average of 72 +/- 26 months. Nondipping HR was defined as a night/day HR ratio greater than 0.90. We chose two outcomes for this analysis: CVD events (defined as stroke, myocardial infarction, or sudden cardiac death) and all-cause mortality. Cox regression analyses (stepwise method) were used to estimate hazard ratios and their 95% confidence interval after adjusting for covariates. RESULTS: In univariate analysis, increased sleep HR and nondipping of HR were associated with increased risk of CVD and all-cause mortality, but awake HR was not. In multivariable analyses, HR nondipping status significantly predicted an increased risk of CVD events (hazard ratio, 2.37; 95% confidence interval, 1.22-4.62; P = 0.01), but not for all-cause mortality. Increased 24-h HR was significantly associated with increased risk of all-cause mortality (hazard ratio, 1.67; 95% confidence interval, 1.11-2.51; P = 0.01). CONCLUSION: The risk of future CVD was shown to be 2.4 times higher in those whose HR does not exhibit the typical nocturnal decline. The relationship was independent of nondipping of SBP and was not dependent on diabetes status or blood pressure level.

Preventing misdiagnosis of ambulatory hypertension: algorithm using office and home blood pressures.

OBJECTIVES: An algorithm for making a differential diagnosis between sustained and white coat hypertension (WCH) has been proposed - patients with office hypertension undergo home blood pressure monitoring (HBPM) and those with normal HBP levels undergo ambulatory blood pressure monitoring (ABPM). We tested whether incorporating an upper office blood pressure (OBP) cut-off in the algorithm, higher than the traditional 140/90 mmHg, reduces the need for HBPM and ABPM. METHODS: Two hundred twenty-nine normotensive and untreated mildly hypertensive participants (mean age 52.5 +/- 14.6 years, 54% female participants) underwent OBP measurements, HBPM, and 24-h ABPM. Using the algorithm, sensitivity, specificity, and positive and negative predictive values (PPV, NPV) for sustained hypertension and WCH were assessed. We then modified the algorithm utilizing a systolic and diastolic OBP cut-off at a specificity of 95% for ambulatory hypertension - those with office hypertension but OBP levels below the upper cut-off underwent HBPM and subsequent ABPM, if appropriate. RESULTS: Using the original algorithm, sensitivity and PPV for sustained hypertension were 100% and 93.8%, respectively. Despite a specificity of 44.4%, NPV was 100%. These values correspond to specificity, NPV, sensitivity, and PPV for WCH, respectively. Using the modified algorithm, the diagnostic accuracy for sustained hypertension and WCH did not change. However, far fewer participants needed HBPM (29 vs. 84) and ABPM (8 vs. 15). CONCLUSION: In this sample, the original and modified algorithms are excellent at diagnosing sustained hypertension and WCH. However, the latter requires far fewer participants to undergo HBPM and ABPM. These findings have important implications for the cost-effective diagnosis of sustained hypertension and WCH.

What is the optimal interval between successive home blood pressure readings using an automated oscillometric device?

OBJECTIVES: To clarify whether a shorter interval between three successive home blood pressure (HBP) readings (10 s vs. 1 min) taken twice a day gives a better prediction of the average 24-h BP and better patient compliance. DESIGN: We enrolled 56 patients from a hypertension clinic (mean age: 60 +/- 14 years; 54% female patients). The study consisted of three clinic visits, with two 4-week periods of self-monitoring of HBP between them, and a 24-h ambulatory BP monitoring at the second visit. Using a crossover design, with order randomized, the oscillometric HBP device (HEM-5001) could be programmed to take three consecutive readings at either 10-s or 1-min intervals, each of which was done for 4 weeks. Patients were asked to measure three HBP readings in the morning and evening. All the readings were stored in the memory of the monitors. RESULTS: The analyses were performed using the second-third HBP readings. The average systolic BP/diastolic BP for the 10-s and 1-min intervals at home were 136.1 +/- 15.8/77.5 +/- 9.5 and 133.2 +/- 15.5/76.9 +/- 9.3 mmHg (P = 0.001/0.19 for the differences in systolic BP and diastolic BP), respectively. The 1-min BP readings were significantly closer to the average of awake ambulatory BP (131 +/- 14/79 +/- 10 mmHg) than the 10-s interval readings. There was no significant difference in patients' compliance in taking adequate numbers of readings at the different time intervals. CONCLUSION: The 1-min interval between HBP readings gave a closer agreement with the daytime average BP than the 10-s interval.