Blood Pressure Monitoring. Task force V: White-coat hypertension

Position of 24-hour ambulatory blood pressure monitoring in modern practice

Currently, 24-hour ambulatory blood pressure (BP) monitoring (ABPM) is the gold standard for diagnosing hypertension (HTN) and evaluating the effectiveness of antihypertensive therapy. The method provides information about some BP parameters that cannot be obtained in any other way. ABPM is reasonable in any patient with a documented increase in BP, especially if specific BP phenotypes are suspected: white coat HTN and masked HTN. Antihypertensive therapy under the ABPM, on average, is more economical and is not associated with overprescribing of drugs and their combinations. Based on the ABPM data, calculating a number of additional indicators of the 24-hour BP profile is possible, but their scope is still limited to the research field. In the conclusion on ABPM data, the results of office BP measurement and antihypertensive therapy should be indicated.

Stress-induced arterial hypertension

Stress is considered as one of the factors associated with the development of many diseases, including the cardiovascular system. The history of studying stress as a risk factor for hypertension began in the first half of the 20th century and continued after the introduction of 24-hour blood pressure monitoring (ABPM) into clinical practice. Then it turned out that there is normotension, stable hypertension and latent hypertension: masked (when clinical BP is within the normal range, and arterial hypertension is recorded according to ABPM and/or self-monitoring of BP) and white coat hypertension (increased BP during a visit to the doctor when normal values of blood pressure according to ABPM or self-monitoring of BP). Currently, both variants of latent hypertension are classified as stress-induced arterial hypertension. Several models have been proposed for the study of stress, but two of them are more common in clinical studies: the Karasek model (based on an imbalance between job demands and job decision latitude) and the Siegrist model (based on an imbalance of effort and reward). There are only few studies in where attempts have been made to link the increase in BP with the parameters of stress response (for example, with hormonal levels) or genetic predisposition. The review discusses the most significant studies of stress-induced arterial hypertension published to date.

Developing the Accuracy of Vital Sign Measurements Using the Lifelight Software Application in Comparison to Standard of Care Methods: Observational Study Protocol

Background

Vital sign measurements are an integral component of clinical care, but current challenges with the accuracy and timeliness of patient observations can impact appropriate clinical decision making. Advanced technologies using techniques such as photoplethysmography have the potential to automate noncontact physiological monitoring and recording, improving the quality and accessibility of this essential clinical information.

Objective

In this study, we aim to develop the algorithm used in the Lifelight software application and improve the accuracy of its estimated heart rate, respiratory rate, oxygen saturation, and blood pressure measurements.

Methods

This preliminary study will compare measurements predicted by the Lifelight software with standard of care measurements for an estimated population sample of 2000 inpatients, outpatients, and healthy people attending a large acute hospital. Both training datasets and validation datasets will be analyzed to assess the degree of correspondence between the vital sign measurements predicted by the Lifelight software and the direct physiological measurements taken using standard of care methods. Subgroup analyses will explore how the performance of the algorithm varies with particular patient characteristics, including age, sex, health condition, and medication.

Results

Recruitment of participants to this study began in July 2018, and data collection will continue for a planned study period of 12 months.

Conclusions

Digital health technology is a rapidly evolving area for health and social care. Following this initial exploratory study to develop and refine the Lifelight software application, subsequent work will evaluate its performance across a range of health characteristics, and extended validation trials will support its pathway to registration as a medical device. Innovations in health technology such as this may provide valuable opportunities for increasing the efficiency and accessibility of vital sign measurements and improve health care services on a large scale across multiple health and care settings.

International Registered Report Identifier (IRRID)

DERR1-10.2196/14326

Impact of Sex on Office White Coat Effect Tail: Investigating Two Italian Residential Cohorts

To assess the impact of sex on office white-coat effect tail (OWCET), the waning of systolic blood pressure (SBP) after its waxing during office visit, on the incidence of long-term major fatal and non-fatal events in two Italian residential cohorts [from the Gubbio Study and the Italian Rural Areas of the Seven Countries Study (IRA)]. There were 3565 persons (92 with missing data, 44% men, 54 ± 11 years) included in the Gubbio and 1712 men (49 ± 5 years) in the IRA studies. OWCET was defined as a decrease of ≥10 mmHg in SBP between successive measurements with slight measurement differences between the two cohorts. Cardiovascular (CVD), coronary heart disease (CHD) and stroke (STR) incidences were considered. Over an approximately 20-year follow-up, women with OWCET had an increased risk of CVD [HR: 1.591 (95%CI: 1.204–2.103)], CHD [HR: 1.614 (95%CI: 1.037–2.512)] and STR [HR: 1.696 (95%CI: 1.123–2.563)] events independently of age, serum and HDL cholesterol, cigarettes, BMI and SBP in the Gubbio study. However, there was no increased risk of CVD, CHD or STR in men with OWCET neither in the Gubbio 20-year follow-up nor in the IRA 50-year follow-up. These results were not modified significantly by the correction of the regression dilutions bias between the first and the subsequent SBP measurements. Thus, in primary care, OWCET should be actively evaluated in women as it can improve stratification of long-term CVD, CHD and STR risks.

Superiority of Out-of-Office Blood Pressure for Predicting Hypertensive Heart Disease in Non-Hispanic Black Adults

Black Americans suffer disproportionately from hypertension and hypertensive heart disease. Out-of-office blood pressure (BP) is more predictive for cardiovascular complications than clinic BP; however, the relative abilities of clinic and out-of-office BP to predict left ventricular hypertrophy in black and white adults have not been established. Thus, we aimed to compare associations of out-of-office and clinic BP measurement with left ventricular hypertrophy by cardiac magnetic resonance imaging among non-Hispanic black and white adults. In this cross-sectional study, 1262 black and 927 white participants of the Dallas Heart Study ages 30 to 64 years underwent assessment of standardized clinic and out-of-office (research staff-obtained) BP and left ventricular mass index. In multivariable-adjusted analyses of treated and untreated participants, out-of-office BP was a stronger determinant of left ventricular hypertrophy than clinic BP (odds ratio per 10 mm Hg, 1.48; 95% CI, 1.34-1.64 for out-of-office systolic BP and 1.15 [1.04-1.28] for clinic systolic BP; 1.71 [1.43-2.05] for out-of-office diastolic BP, and 1.03 [0.86-1.24] for clinic diastolic BP). Non-Hispanic black race/ethnicity, treatment status, and lower left ventricular ejection fraction were also independent determinants of hypertrophy. Among treated Blacks, the differential association between out-of-office and clinic BP with hypertrophy was more pronounced than in treated white or untreated participants. In conclusion, protocol-driven supervised out-of-office BP monitoring provides important information that cannot be gleaned from clinic BP assessment alone. Our results underscore the importance of hypertension management programs outside the medical office to prevent hypertensive heart disease, especially in high-risk black adults. Clinical Trial Registration- URL: https://www.clinicaltrials.gov. Unique identifier: NCT00344903.

Ambulatory monitoring unmasks hypertension among kidney transplant patients: single center experience and review of the literature

Background

Disagreements between clinic and ambulatory blood pressure (BP) measurements are well-described in the general population. Though hypertension is frequent in renal transplant recipients, only a few studies address the clinic-ambulatory discordance in this population. We aimed to describe the difference between clinic and ambulatory BP in kidney transplant patients at our institution.

Methods

We compared the clinic and ambulatory BP of 76 adult recipients of a kidney allograft followed at our transplant center and investigated the difference between these methods, considering confounding by demographic and clinical variables.

Results

Clinic systolic BP (SBP) and diastolic BP (DBP) were 128 ± 13/79 ± 9 mmHg. Awake SBP and DBP were 147 ± 18/85 ± 10 mmHg. The clinic-minus-awake SBP and DBP differences were − 18 and − 6 mmHg, respectively. The negative clinic-awake ΔSBP was more pronounced at age > 60 years (p = 0.026) and with tacrolimus use compared to cyclosporine (p = 0.046). Sleep SBP and DBP were 139 ± 21/78 ± 11 mmHg. A non-dipping sleep BP pattern was noted in 73% of patients and was associated with tacrolimus use (p = 0.020).

Conclusions

Our findings suggest pervasive underestimation of BP when measured in the kidney transplant clinic, emphasizes the high frequency of a non-dipping pattern in this population and calls for liberal use of ambulatory BP monitoring to detect and manage hypertension.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1442-7) contains supplementary material, which is available to authorized users.

Using out-of-office blood pressure measurements in established cardiovascular risk scores: a secondary analysis of data from two blood pressure monitoring studies

BACKGROUND

Blood pressure (BP) measurement is increasingly carried out through home or ambulatory monitoring, yet existing cardiovascular risk scores were developed for use with measurements obtained in clinics.

AIM

To describe differences in cardiovascular risk estimates obtained using ambulatory or home BP measurements instead of clinic readings.

DESIGN AND SETTING

Secondary analysis of data from adults aged 25-84 years in the UK and the Netherlands without prior history of cardiovascular disease (CVD) in two BP monitoring studies: the Blood Pressure in different Ethnic groups (BP-Eth) study and the Home versus Office blood pressure MEasurements: Reduction of Unnecessary treatment Study (HOMERUS).

METHOD

The primary comparison was Framingham risk calculated using BP measured as in the Framingham study or daytime ambulatory BP measurements. Statistical significance was determined using non-parametric tests.

RESULTS

In 442 BP-Eth patients (mean age = 58 years, 50% female [n = 222]) the median absolute difference in 10-year Framingham cardiovascular risk calculated using BP measured as in the Framingham study or daytime ambulatory BP measurements was 1.84% (interquartile range [IQR] 0.65-3.63, P = 0.67). In 165 HOMERUS patients (mean age = 56 years, 46% female) the median absolute difference in 10-year risk for daytime ambulatory BP was 2.76% (IQR 1.19-6.39, P<0.001) and only 8 out of 165 (4.8%) of patients were reclassified.

CONCLUSION

Estimates of cardiovascular risk are similar when calculated using BP measurements obtained as in the risk score derivation study or through ambulatory monitoring. Further research is required to determine if differences in estimated risk would meaningfully influence risk score accuracy.

Prospective external validation of the Predicting Out-of-OFfice Blood Pressure (PROOF-BP) strategy for triaging ambulatory monitoring in the diagnosis and management of hypertension: observational cohort study

OBJECTIVE

To prospectively validate the Predicting Out-of-OFfice Blood Pressure (PROOF-BP) algorithm to triage patients with suspected high blood pressure for ambulatory blood pressure monitoring (ABPM) in routine clinical practice.

DESIGN

Prospective observational cohort study.

SETTING

10 primary care practices and one hospital in the UK.

PARTICIPANTS

887 consecutive patients aged 18 years or more referred for ABPM in routine clinical practice. All underwent ABPM and had the PROOF-BP applied.

MAIN OUTCOME MEASURES

The main outcome was the proportion of participants whose hypertensive status was correctly classified using the triaging strategy compared with the reference standard of daytime ABPM. Secondary outcomes were the sensitivity, specificity, and area under the receiver operator characteristic curve (AUROC) for detecting hypertension.

RESULTS

The mean age of participants was 52.8 (16.2) years. The triaging strategy correctly classified hypertensive status in 801 of the 887 participants (90%, 95% confidence interval 88% to 92%) and had a sensitivity of 97% (95% confidence interval 96% to 98%) and specificity of 76% (95% confidence interval 71% to 81%) for hypertension. The AUROC was 0.86 (95% confidence interval 0.84 to 0.89). Use of triaging, rather than uniform referral for ABPM in routine practice, would have resulted in 435 patients (49%, 46% to 52%) being referred for ABPM and the remainder managed on the basis of their clinic measurements. Of these, 69 (8%, 6% to 10%) would have received treatment deemed unnecessary had they received ABPM.

CONCLUSIONS

In a population of patients referred for ABPM, this new triaging approach accurately classified hypertensive status for most, with half the utilisation of ABPM compared with usual care. This triaging strategy can therefore be recommended for diagnosis or management of hypertension in patients where ABPM is being considered, particularly in settings with limited resources.

Prospective Register Of patients undergoing repeated OFfice and Ambulatory Blood Pressure Monitoring (PROOF-ABPM): protocol for an observational cohort study

INTRODUCTION

The diagnosis and management of hypertension depends on accurate measurement of blood pressure (BP) in order to target antihypertensive treatment appropriately. Most BP measurements take place in a clinic setting, but it has long been recognised that readings taken out-of-office (via home or ambulatory monitoring) estimate true underlying BP more accurately. Recent studies have shown that the change in clinic BP over multiple readings is a significant predictor of the difference between clinic and out-of-office BP. Used in combination with patient characteristics, this change has been shown to accurately predict a patient's out-of-office BP level. The present study proposes to collect real-life BP data to prospectively validate this new prediction tool in routine clinical practice.

METHODS AND ANALYSIS

A prospective, multicentre observational cohort design will be used, recruiting patients from primary and secondary care. All patients attending participating centres for ambulatory BP monitoring will be eligible to participate. Anonymised clinical data will be collected from all eligible patients, who will be invited to give informed consent to permit identifiable data to be collected for data linkage to external outcome registries. Descriptive statistics will be used to calculate the sensitivity, specificity, positive and negative predictive values of the out-of-office BP prediction tool. Area under the receiver operator characteristic curve statistics will be used to examine model performance.

ETHICS AND DISSEMINATION

Ethical approval for this study has been obtained from the National Research. Ethics Service Committee South Central-Oxford A (reference; 15/SC/0184), and site-specific R&D approval has been acquired from the relevant NHS trusts. All findings will be presented at relevant conferences and published in peer-reviewed journals, on the study website and disseminated in lay and social media where appropriate.

Effect of a cheese rich in angiotensin-converting enzyme-inhibiting peptides (Gamalost(®)) and a Gouda-type cheese on blood pressure: results of a randomised trial

Background

High blood pressure (BP) is the leading risk factor for global disease burden, contributing to 7% of global disability adjusted life years. Angiotensin converting enzyme (ACE)-inhibiting bioactive peptides have the potential to reduce BP in humans. These peptides have been identified in many dairy products and have been associated with significant reductions in BP.

Objective

The objective of this trial was to examine whether a cheese rich in ACE-inhibiting peptides (Gamalost^®), or a standard Gouda-type cheese could lower BP.

Design

A total of 153 healthy participants were randomised to one of three parallel arms: Gamalost^® (n=53, 50 g/day for 8 weeks), Gouda-type cheese (n=50, 80 g/day for 8 weeks), and control (n=50). BP and anthropometric measurements were taken at the baseline and at the end, with an additional BP measurement midway. Based on BP at baseline, participants were categorised as having optimal BP (<120/<80 mmHg), normal-high BP (120–139/80–89 mmHg), or being hypertensive (>140/>90 mmHg). Questionnaires about lifestyle, health, and dietary habits were completed at baseline, midway and end.

Results

In total, 148 participants (mean age 43, 52% female) completed the intervention. There were no differences among the three groups in relevant baseline characteristics. BP was reduced in the entire study population, but the cheese groups did not differ from control. However, in a subgroup of participants with slightly elevated BP, BP at 4 weeks of intervention seemed to be borderline significantly more reduced in the Gamalost^® group compared with the control group (Dunnett test: diastolic BP −3.5 mmHg, 95% confidence interval (CI) −7.3, 0.4, systolic BP: −4.3 mmHg, 95% CI −9.8, 1.1).

Conclusion

An intention-to-treat analysis of the data showed no cheese effect upon BP compared to control, but Gamalost^® seemed to have a small, non-significant lowering effect on diastolic BP after 4 weeks in people with a normal-high BP.

Predictors of the Home-Clinic Blood Pressure Difference: A Systematic Review and Meta-Analysis

BACKGROUND

Patients may have lower (white coat hypertension) or higher (masked hypertension) blood pressure (BP) at home compared to the clinic, resulting in misdiagnosis and suboptimal management of hypertension. This study aimed to systematically review the literature and establish the most important predictors of the home-clinic BP difference.

METHODS

A systematic review was conducted using a MEDLINE search strategy, adapted for use in 6 literature databases. Studies examining factors that predict the home-clinic BP difference were included in the review. Odds ratios (ORs) describing the association between patient characteristics and white coat or masked hypertension were extracted and entered into a random-effects meta-analysis.

RESULTS

The search strategy identified 3,743 articles of which 70 were eligible for this review. Studies examined a total of 86,167 patients (47% female) and reported a total of 60 significant predictors of the home-clinic BP difference. Masked hypertension was associated with male sex (OR 1.47, 95% confidence interval (CI) 1.18–1.75), body mass index (BMI, per kg/m² increase, OR 1.07, 95% CI 1.01–1.14), current smoking status (OR 1.32, 95% CI 1.13–1.50), and systolic clinic BP (per mm Hg increase, OR 1.10, 95% CI 1.01–1.19). Female sex was the only significant predictor of white coat hypertension (OR 3.38, 95% CI 1.64–6.96).

CONCLUSIONS

There are a number of common patient characteristics that predict the home-clinic BP difference, in particular for people with masked hypertension. There is scope to incorporate such predictors into a clinical prediction tool which could be used to identify those patients displaying a significant masked or white coat effect in routine clinical practice.

Predicting Out-of-Office Blood Pressure in the Clinic (PROOF-BP): Derivation and Validation of a Tool to Improve the Accuracy of Blood Pressure Measurement in Clinical Practice

Patients often have lower (white coat effect) or higher (masked effect) ambulatory/home blood pressure readings compared with clinic measurements, resulting in misdiagnosis of hypertension. The present study assessed whether blood pressure and patient characteristics from a single clinic visit can accurately predict the difference between ambulatory/home and clinic blood pressure readings (the home-clinic difference). A linear regression model predicting the home-clinic blood pressure difference was derived in 2 data sets measuring automated clinic and ambulatory/home blood pressure (n=991) using candidate predictors identified from a literature review. The model was validated in 4 further data sets (n=1172) using area under the receiver operator characteristic curve analysis. A masked effect was associated with male sex, a positive clinic blood pressure change (difference between consecutive measurements during a single visit), and a diagnosis of hypertension. Increasing age, clinic blood pressure level, and pulse pressure were associated with a white coat effect. The model showed good calibration across data sets (Pearson correlation, 0.48-0.80) and performed well-predicting ambulatory hypertension (area under the receiver operator characteristic curve, 0.75; 95% confidence interval, 0.72-0.79 [systolic]; 0.87; 0.85-0.89 [diastolic]). Used as a triaging tool for ambulatory monitoring, the model improved classification of a patient's blood pressure status compared with other guideline recommended approaches (93% [92% to 95%] classified correctly; United States, 73% [70% to 75%]; Canada, 74% [71% to 77%]; United Kingdom, 78% [76% to 81%]). This study demonstrates that patient characteristics from a single clinic visit can accurately predict a patient's ambulatory blood pressure. Usage of this prediction tool for triaging of ambulatory monitoring could result in more accurate diagnosis of hypertension and hence more appropriate treatment.

Are personality traits associated with white-coat and masked hypertension?

OBJECTIVES

Anxiety and other psychological dispositions are thought to be associated with blood pressure. This study tests whether personality traits have long-term associations with masked and white-coat effects.

METHODS

A community-based sample of 2838 adults from Sardinia (Italy) completed the Revised NEO Personality Inventory, and 7 years later, blood pressure was assessed in the clinic and with ambulatory monitoring. Logistic regressions were used to test whether anxiety, neuroticism, extraversion, openness, agreeableness, and conscientiousness predicted the white-coat and masked hypertension phenomena. Age, sex, and antihypertensive medication use were tested as moderators.

RESULTS

Significant interactions were found between personality traits and antihypertensive medications in predicting masked and white-coat effects. Only among those taking antihypertensive medication, higher anxiety was associated with a higher risk of pseudo-resistant hypertension due to white-coat effect (odds ratio 1.39, 95% confidence interval 1.01-1.91) and higher conscientiousness was associated with a lower risk of masked uncontrolled hypertension (odds ratio 0.70, 95% confidence interval 0.49-0.99). There were no significant interactions with age or sex.

CONCLUSIONS

Among those on antihypertensive medications, anxious individuals were more likely to have pseudo-resistant hypertension due to white-coat effect and less conscientious individuals were at increased risk of masked uncontrolled hypertension. Particularly among anxious and less conscientious individuals, ambulatory monitoring may improve the tailoring of pharmacological treatments.

Predicting out-of-office blood pressure level using repeated measurements in the clinic: an observational cohort study

OBJECTIVES

Identification of people with lower (white-coat effect) or higher (masked effect) blood pressure at home compared to the clinic usually requires ambulatory or home monitoring. This study assessed whether changes in SBP with repeated measurement at a single clinic predict subsequent differences between clinic and home measurements.

METHODS

This study used an observational cohort design and included 220 individuals aged 35-84 years, receiving treatment for hypertension, but whose SBP was not controlled. The characteristics of change in SBP over six clinic readings were defined as the SBP drop, the slope and the quadratic coefficient using polynomial regression modelling. The predictive abilities of these characteristics for lower or higher home SBP readings were investigated with logistic regression and repeated operating characteristic analysis.

RESULTS

The single clinic SBP drop was predictive of the white-coat effect with a sensitivity of 90%, specificity of 50%, positive predictive value of 56% and negative predictive value of 88%. Predictive values for the masked effect and those of the slope and quadratic coefficient were slightly lower, but when the slope and quadratic variables were combined, the sensitivity, specificity, positive and negative predictive values for the masked effect were improved to 91, 48, 24 and 97%, respectively.

CONCLUSION

Characteristics obtainable from multiple SBP measurements in a single clinic in patients with treated hypertension appear to reasonably predict those unlikely to have a large white-coat or masked effect, potentially allowing better targeting of out-of-office monitoring in routine clinical practice.

White coat hypertension and obstructive sleep apnea

PURPOSE

This study aimed to determine blood pressure characteristics and long-term progress in patients with white coat hypertension (WCH) and obstructive sleep apnea (OSA).

METHODS

Systolic blood pressure (SBP) and diastolic blood pressure (DBP) and sleep test results over a period of 26 months were analyzed from WCH patients with OSA (n = 28), WCH patients (n = 23), and healthy control subjects (n = 27).

RESULTS

At the end of observation, WCH patients with OSA presented significantly increased daytime and nighttime BP and lower diurnal difference of SBP (all Ps < 0.05) and the increased rate of "non-dipper" status (SBP 28.6 %, DBP 32.1 %) was significantly higher when compared with WCH and control groups (all Ps < 0.01). Sustained hypertension was observed in 42.8 % of the WCH patients with OSA, which was significantly higher than that in the WCH and control groups (Ps < 0.01) and was predicted by non-dipper status via 24-h ambulatory SBP/DBP monitoring (Ps < 0.05).

CONCLUSION

WCH may represent a prehypertension status, which could develop into sustained hypertension with OSA.

Doctors record higher blood pressures than nurses: systematic review and meta-analysis

BACKGROUND

The magnitude of the 'white coat effect', the alerting rise in blood pressure, is greater for doctors than nurses. This could bias interpretation of studies on nurse-led care in hypertension, and risks overestimating or overtreating high blood pressure by doctors in clinical practice.

AIM

To quantify differences between blood pressure measurements made by doctors and nurses.

DESIGN AND SETTING

Systematic review and meta-analysis using searches of MEDLINE, CENTRAL, CINAHL, Embase, journal collections, and conference abstracts.

METHOD

Studies in adults reporting mean blood pressures measured by doctors and nurses at the same visit were selected, and mean blood pressures extracted, by two reviewers. Study risk of bias was assessed using modified Cochrane criteria. Outcomes were pooled across studies using random effects meta-analysis.

RESULTS

In total, 15 studies (11 hypertensive; four mixed hypertensive and normotensive populations) were included from 1899 unique citations. Compared with doctors' measurements, nurse-measured blood pressures were lower (weighted mean differences: systolic -7.0 [95% confidence interval {CI} = -4.7 to -9.2] mmHg, diastolic -3.8 [95% CI = -2.2 to -5.4] mmHg). For studies at low risk of bias, differences were lower: systolic -4.6 (95% CI = -1.9 to -7.3) mmHg; diastolic -1.7 (95% CI = -0.1 to -3.2) mmHg. White coat hypertension was diagnosed more frequently based on doctors' than on nurses' readings: relative risk 1.6 (95% CI =1.2 to 2.1).

CONCLUSIONS

The white coat effect is smaller for blood pressure measurements made by nurses than by doctors. This systematic difference has implications for hypertension diagnosis and management. Caution is required in pooling data from studies using both nurse- and doctor-measured blood pressures.

Thirty-minute compared to standardised office blood pressure measurement in general practice

BACKGROUND

Although blood pressure measurement is one of the most frequently performed measurements in clinical practice, there are concerns about its reliability. Serial, automated oscillometric blood pressure measurement has the potential to reduce measurement bias and white-coat effect'.

AIM

To study agreement of 30-minute office blood pressure measurement (OBPM) with standardised OBPM, and to compare repeatability.

DESIGN AND SETTING

Method comparison study in two general practices in The Netherlands.

METHOD

Thirty-minute and standardised OBPM was carried out with the same, validated device in 83 adult patients, and the procedure was repeated after 2 weeks. During 30-minute OBPM, blood pressure was measured automatically every 3 minutes, with the patient in a sitting position, alone in a quiet room. Agreement between 30-minute and standardised OBPM was assessed by Bland-Altman analysis. Repeatability of the blood pressure measurement methods after 2 weeks was expressed as the mean difference in combination with the standard deviation of difference (SDD).

RESULTS

Mean 30-minute OBPM readings were 7.6/2.5 mmHg (95% confidence interval [CI] = 6.1 to 9.1/1.5 to 3.4 mmHg) lower than standardised OBPM readings. The mean difference and SDD between repeated 30-minute OBPMs (mean difference = 3/1 mmHg, 95% CI = 1 to 5/0 to 2 mmHg; SDD 9.5/5.3 mmHg) were lower than those of standardised OBPMs (mean difference = 6/2 mmHg, 95% CI = 4 to 8/1 to 4 mmHg; SDD 10.9/6.3 mmHg).

CONCLUSION

Thirty-minute OBPM resulted in lower readings than standardised OBPM and had a better repeatability. These results suggest that 30-minute OBPM better reflects the patient's true blood pressure than standardised OBPM does.

Microalbuminuria in children with primary and white-coat hypertension

Microalbuminuria serves as an early marker of hypertension-related renal damage in adults. However, data on the prevalence of microalbuminuria in paediatric hypertensive patients in general and in children with white-coat hypertension (WCH) specifically are lacking. The aim of our study was to investigate the prevalence of microalbuminuria in children with primary hypertension (PH) and WCH, respectively. This was a retrospective case review of children with PH and WCH treated at three paediatric nephrology centres. Untreated children with either form of hypertension for whom measurements of urinary albumin excretion (UAE) had been performed were enrolled in the study. The study cohort comprised 52 children (39 boys) with hypertension (26 children with PH, 26 with WCH). Microalbuminuria (>3.2 mg/mmol creatinine) was present in 20% of children with PH and none of the children with WCH (p < 0.01). Children with PH had a higher median UAE than those with WCH (1.27 ± 1.92 vs. 0.66 ± 0.46 mg/mmol creatinine, p < 0.05). Based on these results, we suggest that children with PH have an increased prevalence of microalbuminuria, while children with WCH show no signs of hypertension-related renal damage.

Trends in time to confirmation and recognition of new-onset hypertension, 2002-2006

Achieving full benefits of blood pressure control in populations requires prompt recognition of previously undetected hypertension. In 2003, the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure provided definitions of hypertension and recommended that single elevated readings be confirmed within 1 to 2 months. We sought to determine whether the time required to confirm and recognize (ie, diagnose and/or treat) new-onset hypertension decreased from 2002 to 2006 for adult members of 2 large integrated healthcare delivery systems, Kaiser Permanente Northern California and Colorado. Using electronically stored office blood pressure readings, physician diagnoses, and pharmacy prescriptions, we identified 200 587 patients with new-onset hypertension (2002-2006) marked by 2 consecutive elevated blood pressure readings in previously undiagnosed, untreated members. Mean confirmation intervals (time from the first to second consecutive elevated reading) declined steadily from 103 to 89 days during this period. For persons recognized within 12 months after confirmation, the mean interval to recognition declined from 78 to 61 days. However, only 33% of individuals were recognized within 12 months. One third were never recognized during observed follow-up. For these patients, most subsequent blood pressure recordings were not elevated. Higher initial blood pressure levels, history of previous cardiovascular disease, and older age were associated with shorter times to recognition. Times to confirmation and recognition of new-onset hypertension have become shorter in recent years, especially for patients with higher cardiovascular disease risk. Variability in office-based blood pressure readings suggests that further improvements in recognition and treatment may be achieved with more specific automated approaches to identifying hypertension.

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.

The misdiagnosis of hypertension: the role of patient anxiety

BACKGROUND

The white coat effect (defined as the difference between blood pressure [BP] measurements taken at the physician's office and those taken outside the office) is an important determinant of misdiagnosis of hypertension, but little is known about the mechanisms underlying this phenomenon. We tested the hypothesis that the white coat effect may be a conditioned response as opposed to a manifestation of general anxiety.

METHODS

A total of 238 patients in a hypertension clinic wore ambulatory blood pressure monitors on 3 separate days 1 month apart. At each clinic visit, BP readings were manually triggered in the waiting area and the examination room (in the presence and absence of the physician) and were compared with the mercury sphygmomanometer readings taken by the physician in the examination room. Patients completed trait and state anxiety measures before and after each BP assessment.

RESULTS

A total of 35% of the sample was normotensive, and 9%, 37%, and 19% had white coat, sustained, and masked hypertension, respectively. The diagnostic category was associated with the state anxiety measure (F(3,237) = 6.4, P < .001) but not with the trait anxiety measure. Patients with white coat hypertension had significantly higher state anxiety scores (t = 2.67, P < .01), with the greatest difference reported during the physician measurement. The same pattern was observed for BP changes, which generally paralleled the changes in state anxiety (t = 4.86, P < .002 for systolic BP; t = 3.51, P < .002 for diastolic BP).

CONCLUSIONS

These findings support our hypothesis that the white coat effect is a conditioned response. The BP measurements taken by physicians appear to exacerbate the white coat effect more than other means. This problem could be addressed with uniform use of automated BP devices in office settings.

Cost-effectiveness of ambulatory blood pressure monitoring in the initial evaluation of hypertension in children

OBJECTIVE

The goal was to determine the cost-effectiveness of ambulatory blood pressure monitoring in the initial evaluation of stage 1 hypertension.

METHODS

Retrospective chart review of data for children referred to Texas Children's Hospital hypertension clinic between January 2005 and August 2006 was performed. We compared the costs of standard evaluations versus the initial use of ambulatory blood pressure monitoring for children with clinic blood pressure measurements suggesting stage 1 hypertension. Charges for clinic visits, laboratory tests, and imaging were obtained from the Texas Children's Hospital billing department.

RESULTS

A total of 267 children were referred. One hundred thirty-nine children did not receive ambulatory blood pressure monitoring; 54 met clinical indications for ambulatory blood pressure monitoring but did not receive it because it was not a covered expense (44 children) or the family refused the study (10 children). One hundred twenty-six children received clinically indicated ambulatory blood pressure monitoring, paid for either through insurance or by the family. Fifty-eight children (46%) had confirmed white-coat hypertension, 62 (49%) stage 1 hypertension, and 6 (5%) stage 2 hypertension. With the observed prevalence of white-coat hypertension, initial ambulatory blood pressure monitoring use yielded net savings after evaluation of 3 patients, with projected savings of $2.4 million per 1000 patients.

CONCLUSIONS

Ambulatory blood pressure monitoring in the initial evaluation of suspected childhood hypertension is highly cost-effective. Awareness of cost saving potential may increase the availability of ambulatory blood pressure monitoring for evaluation of new-onset hypertension.

Masked hypertension in diabetes mellitus: a potential risk

The prevalence and clinical significance of masked hypertension (MHT) in diabetics have infrequently been described. The authors assessed the association of MHT (defined using a clinic blood pressure [BP] <140/90 mm Hg and daytime ambulatory BP > or = 135/85 mm Hg) with microvascular and macrovascular end organ damage in 81 clinically normotensive Japanese diabetic persons. The prevalence of silent cerebral infarcts (SCIs), increased left ventricular mass, and albuminuria were evaluated. Of 81 patients, 38 (46.9%) were classified as having MHT and showed significantly more SCIs (mean +/- SE: 2.5+/-0.5 vs 1.1+/-0.2; P=.017), and more albuminuria (39% vs 16%; P=.025), but no increase in left ventricular mass index, than the normotensive persons in office and on ambulatory BP monitoring group. The prevalence of MHT in this diabetic population was high (47%). Diabetic patients with MHT showed evidence of brain and kidney damage. Hence, out-of-office monitoring of BP may be indicated in diabetics whose BP is normal in the clinic.

White coat hypertension in childhood: evidence for end-organ effect

OBJECTIVE

To evaluate the hypothesis that white coat hypertension (WCH) represents a prehypertensive state by correlating ambulatory blood pressure monitoring (ABPM) results with BP response to treadmill exercise (TE) and echocardiographic measurement of left ventricular mass index (LVMI) in children with high blood pressure (HBP).

STUDY DESIGN

We evaluated 119 consecutive children age 6 to 18 years (mean = 13.3 years; 65% male) referred for HBP. Office systolic BP (SBP) exceeded the 95th percentile for age/sex/height in all of the children; 10% also had elevated diastolic BP (DBP). WCH was defined as elevated office SBP +/- elevated DBP with normal mean awake ABPM-SBP. ABPM classified 62 subjects as having WCH and 57 as having HBP.

RESULTS

Office BP did not differ between the 2 groups. As defined, awake ABPM-SBP was lower in the WCH group (males: HBP, 142 +/- 12 vs WCH, 124 +/- 5; females: HBP, 137 +/- 8 vs WCH, 121 +/- 5). Awake and asleep DBP and asleep SBP were significantly lower in the WCH group. On TE, maximal SBP exceeded norms for age/sex/body surface area in 63% of the HBP group and 38% of the WCH group. LVMI exceeded the 95th percentile for age/sex in 59% of the males and 90% of the females in the HBP group and in 33% of the males and 36% of the females in the WCH group.

CONCLUSIONS

Exaggerated exercise BP and/or increased LVMI in 62% of those subjects with WCH suggest that this diagnosis in children may represent a prehypertensive state.

Beneficial Effect of Cilnidipine on Morning Hypertension and White-Coat Effect in Patients with Essential Hypertension

Home blood pressure has a higher predictive power for cardiovascular events than office blood pressure, and there is a particularly close association between morning blood pressure at home and the incidence of cardiovascular events and mortality in the early morning. In this study, we evaluated the efficacy of a long-acting N-type and L-type calcium channel blocker, cilnidipine, in reducing morning blood pressure at home and in ameliorating the white-coat effect. Fifty-eight subjects diagnosed with both essential hypertension and morning hypertension (43 currently being treated, 15 new patients) were prescribed cilnidipine at a dosage of 10-20 mg per day for 8 weeks. After the addition of or a change to cilnidipine, the morning systolic blood pressure (SBP) was controlled to less than 135 mmHg in 25 (58%) out of the 43 patients currently receiving antihypertensive medication. The office SBP in 24 out of those 25 patients was also maintained under 140 mmHg. In the 15 newly treated patients, the morning SBP of 12 patients (80%) was controlled to less than 135 mmHg after administration of cilnidipine. At baseline, 17 patients showed a clear white-coat effect, in which the difference between office blood pressure and home blood pressure was 20/10 mmHg or more. The white-coat effect was depressed significantly after cilnidipine administration. These results suggest that cilnidipine may serve as a useful antihypertensive medication in the treatment of morning hypertension, and also attenuate the white-coat effect in patients with essential hypertension.

The Blood Pressure "Uncertainty Range" - a pragmatic approach to overcome current diagnostic uncertainties (II)

A tremendous amount of scientific evidence regarding the physiology and physiopathology of high blood pressure combined with a sophisticated therapeutic arsenal is at the disposal of the medical community to counteract the overall public health burden of hypertension. Ample evidence has also been gathered from a multitude of large-scale randomized trials indicating the beneficial effects of current treatment strategies in terms of reduced hypertension-related morbidity and mortality.In spite of these impressive advances and, deeply disappointingly from a public health perspective, the real picture of hypertension management is overshadowed by widespread diagnostic inaccuracies (underdiagnosis, overdiagnosis) as well as by treatment failures generated by undertreatment, overtreatment, and misuse of medications.The scientific, medical and patient communities as well as decision-makers worldwide are striving for greatest possible health gains from available resources.A seemingly well-crystallised reasoning is that comprehensive strategic approaches must not only target hypertension as a pathological entity, but rather, take into account the wider environment in which hypertension is a major risk factor for cardiovascular disease carrying a great deal of our inheritance, and its interplay in the constellation of other, well-known, modifiable risk factors, i.e., attention is to be switched from one's "blood pressure level" to one's absolute cardiovascular risk and its determinants. Likewise, a risk/benefit assessment in each individual case is required in order to achieve best possible results.Nevertheless, it is of paramount importance to insure generalizability of ABPM use in clinical practice with the aim of improving the accuracy of a first diagnosis for both individual treatment and clinical research purposes. Widespread adoption of the method requires quick adjustment of current guidelines, development of appropriate technology infrastructure and training of staff (i.e., education, decision support, and information systems for practitioners and patients). Progress can be achieved in a few years, or in the next 25 years.

[Effectiveness of self-measurement of blood pressure in patients with hypertension: the Dioampa study]

OBJECTIVE

To evaluate the effectiveness of self-measurement of blood pressure (SMBP) in controlling hypertension.

DESIGN

Randomized, controlled, pragmatic, open study. The unit of randomization was the basic health care unit (BCU), consisting of 1 physician and 1 nurse. All BCUs were randomized to the control group (usual clinical practice, n=94) or to the intervention group (n=86).

SETTING

Primary care BCUs throughout Spain.

PARTICIPANTS

Patients with poorly controlled essential hypertension, defined as systolic blood pressure > or = 140 or diastolic blood pressure > or = 90 mm Hg.

INTERVENTIONS

The patients were given an OMRON HEM-705CP automatic blood pressure monitor on two occasions, for use during 15 days at weeks 6 and 14. Blood pressure was recorded at each visit (baseline, 6, 8, 14, 16, and 24 weeks). Main outcome measures.

MAIN OUTCOME VARIABLE

control of blood pressure, considered systolic/diastolic blood pressure <140/90 mm Hg (130/85 in patients with diabetes).

RESULTS

180 BCUs serving 1325 patients (622 in the intervention group, 703 in the control group) participated. Baseline characteristics were similar in both groups. Immediately after the first period of SMBP (week 8) the proportion of patients whose blood pressure was well controlled was 7.6% higher in the intervention group than in the control group (P=.01). After the second period of SMBP (week 16) the difference between groups decreased to 4.1% (P=.27). At the end of the study the difference was 4.9% (P=.19).

CONCLUSIONS

Self-measurement of blood pressure was effective in controlling blood pressure in the short term, but its effects faded over time.

[Validation of two systems of self-measurement of blood pressure, the OMRON HEM-705 CP and OMRON M1 (HEM 422C2-E) models]

Objective. To validate two monitors on the market for self-measurement of blood pressure (SMBP), an automatic one (OMRON HEM-705 CP) and a semi-automatic one (OMRON M1).Design. Descriptive study of validation of diagnostic tests.Setting. Primary care. San Pablo University Health Centre, Sevilla.Participants. 85 individuals (20 men and 65 women) with a wide range of age and blood pressure (BP), belonging to the population attended at the health centre or to its staff. People with arrhythmia and Korotkoff's V phase close to zero were excluded. Main measurements and results. BP and cardiac frequency (CF) measurements obtained with the SMBP devices to be validated were compared with readings on a mercury sphygmomanometer, used as the standard method. The differences between the SMBP devices and the gold standard were quantified and are presented on the scale proposed by the protocol of the British Hypertension Society (BHS). The mean (SD) of the systolic BP differences (in mm Hg) between the devices evaluated and the standard device was 1.084.73 for the automatic monitor and 1.255.30 for the semi-automatic one. The mean differences of diastolic BP were 0.444.03 for the automatic monitor, and 0.513.90 for the semi-automatic one. The cumulative percentage differences of systolic/ diastolic BP5, 10 and 15 mm Hg were 85.5, 98, 98.8/90.6, 98.4, 100% for the automatic monitor and 82.7, 95.7, 98.8/91, 99.6, 100% for the semi-automatic one. This supposes a Grade A on the BHS procedure, which is maintained on analysis of the results by blood pressure rankings. Conclusion. As both monitors meet the internationally accepted validation criteria, they can be recommended for the monitoring and self-monitoring of BP in patients with hypertension.

Using out of office blood pressure monitoring in the management of hypertension

Self-measurement of blood pressure (BP) and 24-hour ambulatory BP monitoring (ABPM) are increasingly used in order to improve cardiovascular risk stratification over and beyond traditional methods, including sphygmomanometric BP measurement. Self-measured BP has the advantage of being cheap, quite representative of the usual BP over long periods of time, and devoid of the "white coat" effect. Only a few data exist on the prognostic value of self-measured BP. Most of the outcome studies with 24-hour ABPM have been conducted in patients with essential hypertension who were untreated at the time of execution of ABPM. Cardiovascular risk showed a direct association with ambulatory BP and an inverse association with the degree of BP reduction from day to night. White coat hypertension versus ambulatory hypertension and dippers versus nondippers are two classifications based on arbitrary operational risk categories. ABPM may be valuable for refining cardiovascular risk stratification in untreated subjects with office hypertension, as well as those with resistant hypertension.

[Variations in the prevalence and patient profile of white-coat syndrome, according to its definition using self-measurement of blood pressure at home]

OBJECTIVE

To calculate the prevalence of white-coat syndrome (WCS) in patients with hypertension, comparing the two most common definitions and their effect on the profile of the patient with WCS.

DESIGN

Cross-sectional, descriptive study.Setting. Urban health centre.Patients. Hypertense patients selected by simple randomised sampling from among those included in the hypertension programme.

MEASUREMENTS

Clinical blood pressure (CBP) from the previous year was collected. Home blood pressure (HBP) was measured by the patient with an electronic sphygmomanometer. Age, sex, further tests (analysis and electrocardiogram) and other clinical features were also recorded. WCS was defined as when CBP was above/equal to 140/90 mmHg and HBP was under 135/85 mmHg or when the difference between CBP and HBP was more than/equal to 20 mmHg systolic and/or 10 mmHg diastolic pressure.

RESULTS

In 154 hypertense patients (60.4% women) between 38 and 92 years old, mean CBP (141.1/85.3) was higher than mean HBP (136.8/79.8). WCS prevalence varied (p = 0.001), depending on the definition used (20.1% and 36.4%). The systolic and diastolic mean CBP of the last year were higher in those patients with WCS (p < 0.001 for diastolic pressure). The profile of hypertense patients with WCS varied according to the definition used.

CONCLUSIONS

WCS is common in hypertense patients treated in Primary Care and may condition an inadequate assessment of the degree of blood pressure monitoring. As the way of defining WCS conditions its prevalence, its profile and clinical decision-taking, it is essential to agree a uniform definition for practical use.

Treatment of white coat hypertension

White coat hypertension has been defined as the persistent elevation of blood pressure at the clinic or office only. It usually implies that daily ambulatory blood pressure is normal. The accepted cutoff for normal daytime ambulatory blood pressure is 135/85 mm Hg. The prevalence of white coat hypertension is high and varies from 20% to 45%. It appears to be more frequent in women, older patients, and persons with mild hypertension. White coat hypertension should not be confused with the white coat effect. The white coat effect signifies the difference in blood pressure between the office and daytime ambulatory blood pressure and occurs in patients with white coat hypertension as well as in patients with sustained hypertension that is treated or untreated. White coat hypertension is a benign condition, and the incidence of target-organ damage or cardiovascular morbidity and death is not significantly different from that in normotensive persons. Pharmacologic treatment should be withheld; instead, treatment should consist of lifestyle modification, moderate salt restriction, weight reduction, regular exercise, smoking cessation, and correction of glucose and lipid abnormalities. In addition, semiannual or annual follow-up with ambulatory blood pressure monitoring is advised.