Frequency and determinants of white coat hypertension in mild to moderate hypertension: a primary care-based study. Monitorización Ambulatoria de la Presión Arterial (MAPA)-Area 5 Working Group

Sex differences in impact of cumulative systolic blood pressure from childhood to adulthood on albuminuria in midlife: a 30-year prospective cohort study

BACKGROUND AND OBJECTIVES

Albuminuria is recognized as being a predictor of cardiovascular and renal disease. We aimed to identify the impact of the long-term burden and trends of systolic blood pressure on albuminuria in midlife, as well as to explore sex differences concerning this relationship.

METHODS

This longitudinal study consisted of 1,683 adults who had been examined 4 or more times for blood pressure starting in childhood, with a follow-up time period of 30 years. The cumulative effect and longitudinal trend of blood pressure were identified by using the area under the curve (AUC) of individual systolic blood pressure measurement with a growth curve random effects model.

RESULTS

Over 30 years of follow-up, 190 people developed albuminuria, including 53.2% males and 46.8% females (aged 43.39 ± 3.13 years in the latest follow-up). The urine albumin-to-creatinine ratio (uACR) values increased as the total and incremental AUC values increased. Additionally, women had a higher albuminuria incidence in the higher SBP AUC groups than men do (13.3% for men vs. 33.7% for women). Logistic regression showed that the ORs of albuminuria for males and females in the high total AUC group were 1.34 (0.70-2.60) and 2.94 (1.50-5.74), respectively. Similar associations were found in the incremental AUC groups.

CONCLUSIONS

Higher cumulative SBP was correlated with higher uACR levels and a risk of albuminuria in middle age, especially in women. The identification and control of cumulative SBP levels from an early age may assist in reducing the incidences of renal and cardiovascular disease for individuals in later life.

Obstructive sleep apnea and ambulatory blood pressure monitoring: current evidence and research gaps

Obstructive Sleep Apnea (OSA) is a common condition characterized by intermittent collapse of the upper airway during sleep, resulting in partial (hypopnoeas) and total obstructions (apneas). These respiratory events observed in OSA may trigger multiple pathways involved in the blood pressure (BP) instability during the night and potentially influencing daytime BP as well (carry-over effects). This review provides an update about the impact of OSA and its treatments on 24-h BP control. Overall, there is growing evidence suggest that OSA is associated with higher frequency of nondipping BP pattern and nocturnal hypertension in a dose-dependent manner. The presence of nondiping BP (especially the reverse pattern) is independently associated with OSA regardless of sleep-related symptoms suggesting a potential tool for screening OSA in patients with clinical indication for performing ABPM. Beyond dipping BP, preliminary evidence associated OSA with white-coat effect and higher frequency of masked hypertension and BP variability than the control group (no OSA). Unfortunately, most of the evidence on the evidence addressing the impact of OSA treatment on BP was limited to office measurements. In the last years, data from observational and randomized studies pointed that CPAP is able to promote 24-h BP decrease especially in patients with resistant and refractory hypertension. A randomized trial suggests that CPAP is able to decrease the rate of masked hypertension as compared to no treatment in patients with severe OSA. Interestingly, nondipping BP is a good predictor of BP response to CPAP making ABPM an interesting tool for better OSA management.

Diagnostic performance of clinic and home blood pressure measurements compared with ambulatory blood pressure: a systematic review and meta-analysis

BACKGROUND

Clinic blood pressure measurement (CBPM) is currently the most commonly used form of screening for hypertension, however it might have a problem detecting white coat hypertension (WCHT) and masked hypertension (MHT). Home blood pressure measurement (HBPM) may be an alternative, but its diagnostic performance is inconclusive relative to CBPM. Therefore, this systematic review aimed to estimate the performance of CBPM and HBPM compared with ambulatory blood pressure measurement(ABPM) and to pool prevalence of WCHT and MHT.

METHODS

Medline, Scopus, Cochrane Central Register of Controlled Trials and WHO's International Clinical Trials Registry Platform databases were searched up to 23rd January 2020. Studies having diagnostic tests as CBPM or HBPM with reference standard as ABPM, reporting sensitivity and specificity of both tests and/or proportion of WCHT or MHT were eligible. Diagnostic performance of CBPM and HBPM were pooled using bivariate mixed-effect regression model. Random effect model was applied to pool prevalence of WCHT and MHT.

RESULTS

Fifty-eight studies were eligible. Pooled sensitivity, specificity, and diagnostic odds ratio (DOR) of CBPM, when using 24-h ABPM as the reference standard, were 74% (95% CI: 65-82%), 79% (95% CI: 69%, 87%), and 11.11 (95% CI: 6.82, 14.20), respectively. Pooled prevalence of WCHT and MHT were 0.24 (95% CI 0.19, 0.29) and 0.29 (95% CI 0.20, 0.38). Pooled sensitivity, specificity, and DOR of HBPM were 71% (95% CI 61%, 80%), 82% (95% CI 77%, 87%), and 11.60 (95% CI 8.98, 15.13), respectively.

CONCLUSIONS

Diagnostic performances of HBPM were slightly higher than CBPM. However, the prevalence of MHT was high in negative CBPM and some persons with normal HBPM had elevated BP from 24-h ABPM. Therefore, ABPM is still necessary for confirming the diagnosis of HT.

Is Masked Hypertension an underlying Cause of Unexplained Left Ventricle Hypertrophy?

OBJECTIVES

Unexplained left ventricular hypertrophy (ULVH) is defined as increased wall thickness in the absence of conditions that predispose to hypertrophy. The aim of this study was to evaluate the rate of masked hypertension in patient with unexplained left ventricle hypertrophy.

METHOD

A total of 120 consecutive unexplained left ventricle hypertrophy patients without overt hypertension and diabetes and 121 healthy control subjects were included in the study. After a complete medical history and laboratory examination, patients' height, weight, waist circumference heart rate, and office blood pressure were recorded. All subjects underwent ambulatory blood pressure monitoring, and transthoracic echocardiography.

RESULTS

Mean age were similar between patients with ULVH and controls. There was no significant difference in total cholesterol, HDL, LDL cholesterol and triglyceride levels, left ventricle ejection fraction, between the groups. Prevalence of Masked hypertension was significantly higher in patients with ULVH than controls (28.3% vs 6.6%, p < .001). Left ventricular mass index (141.9 ± 16.8 g/cm² vs. 67.3 ± 10.3 g/cm², p < .001) was significantly higher in masked hypertensive patients with ULVH compared to normotensive ULVH and control subjects.

CONCLUSION

In this study, we found high prevalence of masked hypertension in ULVH patients. Patients with ULVH should be screened by ABPM to detect possible masked hypertension.

Decoding white coat hypertension

There is arguably no less understood or more intriguing problem in hypertension that the "white coat" condition, the standard concept of which is significantly blood pressure reading obtained by medical personnel of authoritative standing than that obtained by more junior and less authoritative personnel and by the patients themselves. Using hospital-initiated ambulatory blood pressure monitoring, the while effect manifests as initial and ending pressure elevations, and, in treated patients, a low daytime profile. The effect is essentially systolic. Pure diastolic white coat hypertension appears to be exceedingly rare. On the basis of the studies, we believe that the white coat phenomenon is a common, periodic, neuro-endocrine reflex conditioned by anticipation of having the blood pressure taken and the fear of what this measurement may indicate concerning future illness. It does not change with time, or with prolonged association with the physician, particularly with advancing years, it may be superimposed upon essential hypertension, and in patients receiving hypertensive medication, blunting of the nighttime dip, which occurs in about half the patients, may be a compensatory mechanisms, rather than an indication of cardiovascular risk. Rather than the blunted dip, the morning surge or the widened pulse pressure, cardiovascular risk appears to be related to elevation of the average night time pressure.

White-coat hypertension, as defined by ambulatory blood pressure monitoring, and subclinical cardiac organ damage: a meta-analysis

AIM

: The clinical and prognostic relevance of white-coat hypertension (WCH) has not been fully elucidated; in particular, the association of this blood pressure phenotype with suclinical organ damage remains unclear. We performed a systematic meta-analysis in order to provide a comprehensive information on cardiac structural and functional changes in WCH, as defined by ambulatory blood pressure monitoring.

DESIGN

Studies were identified by the following search terms: 'white-coat hypertension', 'isolated clinic hypertension', 'cardiac organ damage', 'target organ damage', 'left ventricle', 'left ventricular hypertrophy', 'cardiac hypertrophy', 'ventricular dysfunction', and 'echocardiography'.

RESULTS

A total of 7382 untreated adult patients (2493 normotensive, 1705 WCH, and 3184 hypertensive individuals) included in 25 studies were considered. Left ventricular mass index was higher in WCH than in normotensive patients [standardized difference in mean (SDM) 0.50, P < 0.01]; mitral E/A ratio was lower (SDM -0.27, P < 0.01) and left atrium larger (SDM 0.29, P < 0.05) in WCH than in the normotensive counterparts. Hypertensive patients showed a greater left ventricular mass index (SDM 0.42, P < 0.01), reduced E/A (SDM -0.15, P < 0.01), and larger left atrium diameter (SDM 0.27, P < 0.01) than WCH patients.

CONCLUSIONS

Our meta-analysis shows that alterations in cardiac structure and function in WCH patients, as defined by ambulatory blood pressure monitoring, are intermediate between sustained hypertensive patients and normotensive controls. The study supports the view that WCH should not be further considered a fully benign entity.

Screening for high blood pressure in adults: U.S. Preventive Services Task Force recommendation statement

DESCRIPTION

Update of the 2007 U.S. Preventive Services Task Force (USPSTF) reaffirmation recommendation statement on screening for high blood pressure in adults.

METHODS

The USPSTF reviewed the evidence on the diagnostic accuracy of different methods for confirming a diagnosis of hypertension after initial screening and the optimal rescreening interval for diagnosing hypertension.

POPULATION

This recommendation applies to adults aged 18 years or older without known hypertension.

RECOMMENDATION

The USPSTF recommends screening for high blood pressure in adults aged 18 years or older. (A recommendation) The USPSTF recommends obtaining measurements outside of the clinical setting for diagnostic confirmation before starting treatment.

Diagnostic and predictive accuracy of blood pressure screening methods with consideration of rescreening intervals: a systematic review for the U.S. Preventive Services Task Force

BACKGROUND

Elevated blood pressure (BP) is the largest contributing risk factor to all-cause and cardiovascular mortality.

PURPOSE

To update a systematic review on the benefits and harms of screening for high BP in adults and to summarize evidence on rescreening intervals and diagnostic and predictive accuracy of different BP methods for cardiovascular events.

DATA SOURCES

Selected databases searched through 24 February 2014.

STUDY SELECTION

Fair- and good-quality trials and diagnostic accuracy and cohort studies conducted in adults and published in English.

DATA EXTRACTION

One investigator abstracted data, and a second checked for accuracy. Study quality was dual-reviewed.

DATA SYNTHESIS

Ambulatory BP monitoring (ABPM) predicted long-term cardiovascular outcomes independently of office BP (hazard ratio range, 1.28 to 1.40, in 11 studies). Across 27 studies, 35% to 95% of persons with an elevated BP at screening remained hypertensive after nonoffice confirmatory testing. Cardiovascular outcomes in persons who were normotensive after confirmatory testing (isolated clinic hypertension) were similar to outcomes in those who were normotensive at screening. In 40 studies, hypertension incidence after rescreening varied considerably at each yearly interval up to 6 years. Intrastudy comparisons showed at least 2-fold higher incidence in older adults, those with high-normal BP, overweight and obese persons, and African Americans.

LIMITATION

Few diagnostic accuracy studies of office BP methods and protocols in untreated adults.

CONCLUSION

Evidence supports ABPM as the reference standard for confirming elevated office BP screening results to avoid misdiagnosis and overtreatment of persons with isolated clinic hypertension. Persons with BP in the high-normal range, older persons, those with an above-normal body mass index, and African Americans are at higher risk for hypertension on rescreening within 6 years than are persons without these risk factors.

PRIMARY FUNDING SOURCE

Agency for Healthcare Research and Quality.

[Reproducibility of arterial pressure measured in the ELSA-Brasil with 24-hour pressure monitoring]

OBJECTIVE

To determine the reproducibility of casual arterial pressure measurement and to confirm pressure diagnosis by monitoring of participants in the ELSA-Brasil (Estudo Longitudinal de Saúde do Adulto - Brazilian Longitudinal Study for Adult Health).

METHODS

Casual blood pressure was measured with an oscilometric device. A sub-sample of participants (N = 255) from Espírito Santo state (Southeastern Brazil) was reevaluated using the same methodology following one to ten weeks and, in addition, underwent arterial blood pressure monitoring. Diagnosis of hypertension used cut off points of 140/90 mmHg for casual pressure and 130/80 mmHg for arterial blood pressure monitoring. White coat hypertension was defined as the presence of hypertension in casual blood pressure and normal arterial blood pressure monitoring, and converse findings characterized masked hypertension.

RESULTS

Data are from 230 participants that on the two occasions were free from antihypertensive medication (N1 = 153) or under the same antihypertensive regimen (N2 = 77). Normotension was confirmed by arterial blood pressure monitoring in 120 out of 134 participants of the N1 group. In N2, blood pressure control was confirmed by arterial blood pressure monitoring in 43 of 54 participants with controlled hypertension per casual blood pressure. Overall diagnostic concordance between casual blood pressure and arterial blood pressure monitoring was 78% (kappa = 0.44). In the N1 group, six subjects (4%) presented white coat hypertension, and 23 subjects (25%) presented with masked hypertension.

CONCLUSIONS

Diagnostic concordance between casual blood pressure and arterial blood pressure monitoring was moderate. The rigorous standardization of casual blood pressure measurement adopted in the ELSA-Brasil study was able to reduce white coat hypertension. The high frequency of masked hypertension may suggest that pressure values obtained by arterial blood pressure monitoring indicate an elevated degree of stress at work.

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.

Pre-anesthesia systolic blood pressure increases with age regardless of sex

PURPOSE

Pre-anesthesia hypertension (PAH) is the temporary elevation of blood pressure (BP), compared with normal ambulatory recorded BP or self-measured BP at home, in patients waiting for operation in the operating room (OR) before anesthesia induction. In general, the incidence of sustained hypertension (SH) increases progressively with age and the increase is greater in males than in females. In this study, we investigated the influence of age and sex on PAH.

METHODS

Sampling data on consecutive patients who were more than 20 years old and who had undergone surgery under general, intrathecal, or epidural anesthesia were retrospectively collected from hospital records and anesthesia records. Patients with SH, which was defined as a past history of hypertension and taking oral antihypertensive medications, were excluded from the analyses, and the data of 231 patients, 102 males and 129 females, were used for the analyses.

RESULTS

The proportions of male and female patients with a systolic BP (sBP) of more than 140 mmHg in the OR before anesthesia induction were 55.9 and 42.6%, respectively. The proportions of male and female patients with a diastolic BP (dBP) of more than 90 mmHg were 34.3 and 23.3%, respectively. There was no difference in the proportions of male and female patients with PAH. The differences in sBP between measurements in the hospital room (HR) before the operation and those in the OR (ΔsBP) in males and females were 22.9 ± 25.6 and 19.0 ± 24.0 mmHg, respectively. The differences in dBP between measurements in the HR and those in the OR (ΔdBP) in males and females were 12.7 ± 16.5 and 8.4 ± 17.9 mmHg, respectively. There were no differences in ΔsBP and ΔdBP between males and females. The sBP in the OR and the ΔsBP increased significantly with age in both males and females.

CONCLUSION

Age is an important clinical factor related to PAH. Pre-anesthesia sBP and the change in pre-anesthesia sBP increase progressively with age regardless of sex. These findings suggest that the higher BP seen in the elderly in the OR before anesthesia induction, as reported previously, might be explained in part by a greater impact of PAH in older people.

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.

Assessment of the white-coat effect among hypertensive patients presumed to be at goal

BACKGROUND

There are limited studies that explore the rate of existent uncontrolled hypertension versus a significant white-coat effect. Likewise, few studies have described the physician's response to the results of an ambulatory blood pressure monitoring (ABPM) study.

OBJECTIVE

To determine the percentage of treated hypertensive patients referred for ABPM based on discrepant office and home blood pressures who had achieved goal blood pressure and to determine the degree of white-coat effect in these patients.

METHODS

Medical records of 222 consecutive patients were reviewed. Patients without a clinic visit since a medication change and those with <70% valid readings on ABPM were excluded. The proportion of patients at their goal blood pressure during ABPM was determined. Clinic blood pressure readings prior to ABPM were compared to daytime ABPM readings to calculate the white-coat effect. The percentage of patients whose blood pressure decreased by 10% or more in the night interval versus the daytime period was calculated. Changes to antihypertensive therapy were determined for the 6-month post-ABPM period.

RESULTS

One hundred ninety-three patients met the inclusion criteria. Mean (SD) clinic blood pressure was 158/77 (13/10) mm Hg, compared to mean daytime ABPM readings of 127/70 (12/9) mm Hg. Sixty-seven percent of patients were at goal blood pressure. The mean white-coat effect was 31/7 (16/9) mmHg and was significantly greater in patients who were at goal versus those who were not (p < 0.01). A 10% or higher overnight dip occurred in 28% of those at goal. Therapy was not escalated 6 months after ABPM in 91% of patients who were at goal during the test despite a mean post-ABPM clinic blood pressure of 151/74 mm Hg.

CONCLUSIONS

The majority of patients with incongruent clinic and home blood pressure readings were at goal after ABPM evaluation. Further study is needed regarding demographic or clinical characteristics that can be used to help predict which patients may be experiencing a significant white-coat effect and are actually at goal in an ambulatory setting.

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.

Target organ status in white-coat hypertensives: usefulness of serum procollagen type I propeptide in the respect of left ventricular diastolic dysfunction

BACKGROUND

Myocardial fibrosis is a feature of diastolic dysfunction and target organ damage, which was compared among subjects with normotension (NT), white-coat hypertension (WCH) and essential hypertension (EH). Serum procollagen type I propeptide (PIP) level was assessed as a marker of diastolic dysfunction in WCH.

METHODS AND RESULTS

Of 90 subjects, 30 had NT and 30 had WCH (ambulatory daytime blood pressure <135/85 mmHg) and 30 had EH (untreated mild to moderate hypertension); all underwent biochemical and echocardiographic examinations. Those with WCH had a lower left ventricular (LV) mass index than those with EH, but it was higher than in the NT group. WCH patients had a lower mitral valve E/A ratio and a higher LV E/E' (E': septal mitral annular peak velocity) ratio than NT patients, whereas these values were higher and lower respectively than in the EH group. The LV E/E' ratio, an estimate of LV diastolic function, correlated with the serum PIP concentration in WCH patients (r=0.39, P=0.03).

CONCLUSION

WCH is an intermediate group between NT and EH in respect of target organ damage. These results show a relationship between LV diastolic function and serum PIP in WCH, so the serum PIP level may be a useful marker of diastolic dysfunction and target organ damage in such patients.

Comparing the effects of white coat hypertension and sustained hypertension on mortality in a UK primary care setting

PURPOSE

We examined all-cause mortality within a primary care setting in patients with white coat hypertension or sustained hypertension in whom blood pressure (BP) monitoring was indicated.

METHODS

This prospective multicenter study of ambulatory BP monitoring included 48 family practices in the county of Oxfordshire, United Kingdom. Mortality was compared for patients having white coat hypertension (mean of 3 clinic BP readings >140/90 mm Hg and daytime ambulatory readings< or =135/85 mm Hg) and patients having sustained hypertension (mean of 3 clinic readings >140/90 mm Hg and daytime ambulatory readings >135/85 mm Hg).

RESULTS

A routine primary care cohort consisting of 5,182 patients chosen to undergo ambulatory BP monitoring by their family physician was followed up for a median of 7.3 years (interquartile range, 5.8-8.9). There were 335 deaths (6.5%), corresponding to a mortality rate of 8.9 deaths (95% confidence interval [CI], 8.0-9.9) per 1,000 years of follow-up. Patients with white coat hypertension (n = 1,117) were more likely to be female and were on average younger than patients with sustained hypertension (n = 4,065). The unadjusted rate of all-cause mortality in patients with white coat hypertension was lower, at 4.4 deaths per 1,000 years of follow-up (95% CI, 3.1-6.0) than that in patients with sustained hypertension, at 10.2 deaths per 1,000 years of follow-up (95% CI, 9.1-11.4). This reduction in all-cause mortality was still clinically significant after adjustment for age, sex, smoking, use of antihypertensive medication, and practice-clustering effects (hazard ratio = 0.64; 95% CI, 0.42-0.97; P=.04).

CONCLUSIONS

White coat hypertension (elevation of clinic BP only) confers significantly less risk of death than sustained hypertension (elevation of both clinic and ambulatory BPs). Trials are now needed to evaluate the risk reduction achievable in patients who have white coat hypertension and are receiving BP-lowering therapy.

Sex differences in ambulatory blood pressure monitoring

PURPOSE

Referral to ambulatory blood pressure monitoring may have bearing upon blood pressure control and prognosis. We describe sex-related differences in referral for ambulatory monitoring and their prognostic impact.

METHODS

Between 1991 and 2005, 3957 patients were monitored in our ambulatory monitoring service, of whom 2114 (53%) were women. Demographic and clinical data were analyzed according to sex.

RESULTS

Age (58+/-15 vs 52+/-17 years, respectively) and body mass index (27.5+/-4.9 vs 26.9+/-4.0 kg/m(2), respectively) were higher in women than men. Treatment for hypertension was more prevalent in women (62% vs 53%, respectively). Clinic systolic blood pressure (148+/-24 vs 146+/-20 mm Hg, respectively) and clinic pulse pressure (65+/-22 vs 59+/-18 mm Hg, respectively) were higher in women compared with men. In women, the white-coat effect was increased, compared with men; 5.2+/-12.4% vs 1.5+/-10.7% systolic, and 5.4+/-11.2% vs 3.6+/-10.3% diastolic. Consequently, women had lower ambulatory blood pressure than men. In women, 24-hour blood pressure was 136+/-17/76+/-10 vs 140+/-15/81+/-10 mm Hg in men, awake blood pressure 141+/-17/80+/-11 vs 144+/-15/84+/-10 mm Hg, and sleep blood pressure was 125+/-19/67+/-10 vs 127+/-18/71+/-11 mm Hg. Age-adjusted ambulatory blood pressure also was lower in women. Ambulatory heart rate was higher in women (P <.0001). Kaplan-Meier survival did not differ by sex (P=.66), despite older age and higher clinic blood pressure.

CONCLUSIONS

The results might imply that referral was driven by the physicians' overall patient risk perception. The greater magnitude of white-coat effect in women, and correspondingly lower ambulatory blood pressure, might in part account for similar mortality in the face of older age and higher clinic blood pressure.

Mechanical and circulating biomarkers in isolated clinic hypertension

1. This review examines the current evidence for altered mechanical and circulating biomarkers in isolated clinic hypertension and their potential significance. 2. Arterial stiffness, as assessed by central pulse wave velocity, is influenced by multiple cardiovascular risk factors; however, an independent association with isolated clinic hypertension (ICHT) has not been convincingly shown in four small studies. 3. Endothelial dysfunction, as assessed by brachial artery flow-mediated vasodilation, circulating levels of endothelial markers (e.g. nitrite/nitrate, von Willebrand factor, endothelin-1) and/or circulating levels of inhibitors of vascular nitric oxide (plasma asymmetric dimethylarginine, homocysteine), has been shown to be present in established hypertension and to a variable and inconsistent extent in subjects with ICHT. 4. Evidence of increased oxidative stress in ICHT versus normotensive subjects was found in two of three studies. 5. Circulating inflammatory markers C-reactive protein and plasminogen activator inhibitor-1 were significantly increased in two of three and two of two studies, respectively, in ICHT compared with normotensive subjects. 6. Urinary albumin excretion is a marker of both arterial and renal disease. The consensus from seven studies in patients with ICHT is that albuminuria is not an independent marker for ICHT. 7. Studies to date assessing biomarkers in ICHT have been small and cross-sectional. Larger, long-term longitudinal studies of arterial functional and circulating biomarkers are required to assess the potential vascular impact of ICHT.

Prevalence, predictive factor, and clinical significance of white-coat hypertension and masked hypertension in Korean hypertensive patients

BACKGROUND

The prevalence and clinical significance of white-coat hypertension (WCHT) and masked hypertension (MHT) are unknown in Koreans. Here we measure the frequency of WCHT and MHT in hypertensive subjects and identify the epidemiologic and/or clinical factors that predict it in Korean subjects.

METHODS

This study is a retrospective analysis of a random sample from February 2004 to October 2005. All patients had measurements of blood pressure (BP) in the clinic and 24-hour ambulatory blood pressure monitoring (ABPM). Subjects were classified into four groups on the basis of daytime ambulatory BP and clinic BP level: 1) Normotension (NT), 2) MHT, 3) WCHT, and 4) sustained hypertension (SHT).

RESULTS

For all 967 patients, the mean clinic BP was 157.7 +/- 22.0/ 95.3 +/- 13.1 mmHg, and the mean daytime ambulatory BP was 136.4 +/- 15.0/ 86.2 +/- 10.7 mmHg. The NT, MHT, WCHT, and SHT groups consisted of 51 (5.3%), 55 (5.7%), 273 (28.2%), and 588 (60.8%) subjects, respectively. The left ventricular mass index was significantly higher in SHT than in the other groups, and was positively correlated with BP, especially ABPM. Compared with NT, the factors associated with MHT were younger age, male gender, higher BMI, clinic BP > or = 130 mmHg, and alcohol consumption. Compared with SHT, the factors associated with WCHT were female gender, lower BMI, and clinic BP < 150 mmHg.

CONCLUSIONS

WCHT and MHT were prevalent in the hypertensive population. ABPM was more predictive of target organ damage than clinic BP, and could be useful in identifying subjects at risk for WCHT and MHT.

How reliable is isolated clinical hypertension defined by a single 24-h ambulatory blood pressure monitoring?

BACKGROUND

Isolated clinical hypertension (ICH) is characterized by a persistently elevated clinic blood pressure in the presence of a normal day-time or 24-h ambulatory blood pressure (ABP). This definition is based on a single ABP monitoring (ABPM) and little attention has been focused on the reproducibility of this condition.

OBJECTIVE

To investigate the reliability of the criteria currently recommended by major hypertension guidelines to detect ICH based on a single 24-h ABPM session.

METHODS

A total of 611 never-treated grade 1 and 2 hypertensive patients (mean age 46 +/- 12 years) referred for the first time to our out-patient clinic, underwent repeated clinic blood pressure measurements, routine investigations, two 24-h periods of ABPM 1-4 weeks apart, cardiac and carotid ultrasound examinations. ABPM was always performed over a working day and the same daily activities were recommended during the two periods. ICH was diagnosed by the following criteria: (i) mean daytime values < 135/85 mmHg or (ii) mean 24-h blood pressure values < 125/80 mmHg during the first ABPM.

RESULTS

The overall prevalence of ICH was 7.1% according to criterion (i) and 5.4% according to criterion (ii). Twenty (46.6%) of the 43 patients with mean daytime blood pressure values < 135/85 mmHg during the first ABPM, exceeded this cut-off value during the second ABPM period. Twenty-two (66.6%) of the 33 patients with mean 24-h blood pressure values < 120/80 mmHg during the first ABPM did not confirm a normal blood pressure profile during the second ABPM recording. Cardiovascular involvement was significantly lower in subjects with persistent normal ABP compared to those with non-reproducible ICH pattern or sustained hypertensives.

CONCLUSIONS

These findings clearly indicate that: (i) the classification of ICH on the basis of a single ABPM, using the cut-offs suggested by major hypertension guidelines, has a limited short-term reproducibility and (ii) repeated ABPM recordings should be recommended to correctly diagnose patients with ICH and improve cardiovascular risk stratification.

Effectiveness of Blood Pressure Control Outside the Medical Setting

We studied the effectiveness of blood pressure (BP) control outside the clinic by using ambulatory BP monitoring (ABPM) among a large number of hypertensive subjects treated in primary care centers across Spain. The sample consisted of 12 897 treated hypertensive subjects who had indications for ABPM. Office-based BP was calculated as the average of 2 readings. Twenty-four–hour ABPM was then performed using a SpaceLabs 90207 monitor under standardized conditions. A total of 3047 patients (23.6%) had their office BP controlled, and 6657 (51.6%) were controlled according to daytime ABPM. The proportion of office resistance or underestimation of patients’ BP control by physicians in the office (office BP ≥140/90 mm Hg and average daytime ambulatory BP <135/85 mm Hg) was 33.4%, and the proportion of isolated office control or overestimation of control (office BP <140/90 mm Hg and average daytime ambulatory BP ≥135/85 mm Hg) was 5.4%. BP control was more frequently underestimated in patients who were older, female, obese, or with morning BP determination than in their counterparts. BP control was more frequently overestimated in those who were younger, male, nonobese, smokers, or with evening BP determination. Ambulatory-based hypertension control was far better than office-based hypertension control. This conveys an encouraging message to clinicians, namely that they are actually doing better than is evidenced by office-based data. However, the burden of underestimation and overestimation of BP control at the office is still remarkable. Physicians should be aware that the likelihood of misestimating BP control is higher in some hypertensive subjects.

[Home blood pressure self-monitoring. Influence of the mean calculation used on the diagnosis of white-coat hypertension]

OBJECTIVE

To describe the variations in the diagnosis performance of home blood pressure self-monitoring (hBPSM) with different methods for mean calculation, in order to diagnose white-coat hypertension (WCH).

DESIGN

Multi-centre, descriptive, and comparative study to assess the diagnosis performance of a test method.

SETTING

Four primary health care centres.

PARTICIPANTS

A total of 157 recently-diagnosed, untreated patients with mild-moderate hypertension took part in the study.

METHODS

The results obtained with hBPSM (3 consecutive days with readings in triplicate, morning-night) were compared with a "gold standard" out-patient blood pressure reading (OutBP).

RESULTS

Systolic and diastolic BP values of the first day and first reading (morning-night) were higher than the remaining days and readings (linear trend P< .001). Results in hBPSM diagnostic performance using all readings to calculate the mean were: sensitivity (S), 47.6%; specificity (Sp), 77.4%; positive and negative predictive values (PPV and NPV), 58.8% and 68.6%, with positive and negative probability coefficients (PPC and NPC), 2.10 and 0.67. When readings with greater patient alarm reaction (first day and first reading, morning-night) were removed, greater values of S (61.9%) were obtained, albeit at expense of an excessive loss in Sp (64.5%) and without improvement in PPC (1.74).

CONCLUSIONS

The diagnostic performance of hBPSM in WCH was low and failed to improve with the use of different systems to calculate mean BP.

Daytime ambulatory systolic blood pressure is more effective at predicting mortality than clinic blood pressure

OBJECTIVES

To assess the prognostic value of daytime ambulatory blood pressure compared with routine clinic blood pressure in determining mortality.

METHODS

Prospective multicentre study in 48 general practices in Oxfordshire, a hypertension clinic in Oxford and a hypertension clinic in London.

RESULTS

A cohort of 10 129 patients from Oxford and London was followed up for a median of 8.2 years. Nine hundred and one deaths were recorded (8.9%) corresponding to a mortality rate per 1000 years of follow-up of 10.8 (99% confidence interval 9.9-11.8). Comparing the highest quartile for systolic ambulatory blood pressure with the lowest (>or=160 vs. <135 mmHg) gives an estimated age sex-adjusted hazard ratio for mortality of 1.51 (95% confidence interval 1.25-1.83, P<0.001). The corresponding comparison for clinic systolic blood pressure (>or=174 vs. <148 mmHg) results in a hazard ratio of 1.02 (95% confidence interval 0.84-1.24, P=0.9). Comparing ambulatory versus clinic systolic blood pressure (10 mmHg groupings) using nested statistical modelling, removal of the ambulatory blood pressure term from the baseline Cox model (nine 10 mmHg categories) resulted in a highly significant likelihood ratio test statistic of 52.5 (df=8, P<0.0001). The corresponding result for removal of the clinic blood pressure term was 18.1 (df=8, P=0.02), thus reinforcing the finding that ambulatory blood pressure monitoring has greater prognostic significance. Ambulatory blood pressure was also a better predictor of all-cause mortality both in patients taking medication and those not taking medication at the time of monitoring.

CONCLUSION

Daytime ambulatory blood pressure monitoring is a much better prognostic indicator of all-cause mortality than clinic blood pressure.

Home blood pressure in poorly controlled hypertension: relationship with ambulatory blood pressure and organ damage

OBJECTIVES

(1) To assess whether home blood pressure measurement is a reliable alternative to ambulatory blood pressure monitoring for the evaluation of treated patients with inadequate blood pressure control at the clinic; and (2) to evaluate the relationship between home blood pressure and several target-organ damage markers.

BASIC METHODS

A cross-sectional study was performed in 225 treated hypertensive patients with persistently high blood pressure values at the clinic (systolic blood pressure 140 mmHg and/or diastolic blood pressure 90 mmHg). All study participants underwent clinic blood pressure measurement, 24-h ambulatory blood pressure and home blood pressure monitoring. A subgroup of patients underwent the following procedures: carotid echography (n=74), microalbuminuria determination (n=88) and echocardiography (n=43). We defined out-of-clinic normotension as an average ambulatory or home blood pressure less than 135 mmHg (systolic) and 85 mmHg (diastolic).

MAIN RESULTS

The sensitivity, specificity and positive and negative predictive values of the home blood pressure method for predicting out-of-clinic normotension (with the ambulatory method used as reference), expressed as percentages, were 50, 87, 64 and 79%, respectively. Systolic home blood pressure correlated significantly with left ventricular mass (r=0.33, P<0.05) and microalbuminuria (r=0.24, P<0.05). Similar correlation coefficients were found for systolic ambulatory blood pressure (r=0.32, P<0.05 and r=0.24, P<0.05, respectively). Clinic blood pressure did not correlate with either left ventricular mass or microalbuminuria (r=0.19, P=0.09 and r=0.19, P=0.24, respectively). Diastolic home blood pressure, but not ambulatory blood pressure, correlated negatively with mean carotid intima-media thickness (r=-0.27, P<0.05).

CONCLUSION

Our results suggest that, in patients with poorly controlled hypertension at the clinic, home blood pressure represents a complementary test rather than an alternative to ambulatory blood pressure, and correlates with several target-organ damage markers.

Análisis de las áreas de mejora del control de la hipertensión arterial en Atención Primaria

BACKGROUND AND OBJECTIVES

Most hypertensive patients do not have their blood pressure (BP) under control. This study aims to evaluate Primary Care physicians' management of hypertension by analyzing the four main areas proposed by experts to improve BP control.

MATERIAL AND METHODS

From February to May 2003 a questionnaire was completed by 195 Primary Care physicians from 33 Primary Care centers of Madrid, Spain. Four aspects of clinical practice were examined: a) knowledge of hypertension guidelines and objectives; b) diagnosis and follow-up of patients; c) hypertension treatment, and d) drug compliance.

RESULTS

Guidelines were followed by 90.6% of the physicians. Twenty six percent of the physicians perceived that guideline objectives are too strict and only 32% identified systolic BP as the component that provides more risk. Only 14% used automatic devices to measure BP while 89% still use the mercury sphygmomanometer. Diuretics were included among the 3 most used antihypertensive drugs by 94% of the physicians, ACEI by 91%, beta blockers by 62% and combinations only by 24%. Eighty eight percent believed that more than 40% of their patients have their BP under control and 53% felt that less than 20% of their patients were non-compliant with antihypertensive treatment.

CONCLUSIONS

Hypertension management among Primary Care physicians showed some deficiencies in the 4 analyzed areas. Thus, perception of excessively rigorous guideline objectives, underrating of systolic BP, underuse of automatic devices and drug associations, and the overestimation of BP control and therapeutic compliance are specific areas that should be modified to improve BP control.

Home blood pressure self-monitoring: diagnostic performance in white-coat hypertension

OBJECTIVE

To determine the diagnostic performance of home blood pressure self-monitoring in white-coat hypertension using a 3-day reading program.

MATERIAL AND METHODS

One hundred and ninety nontreated patients recently diagnosed with mild-moderate hypertension, selected consecutively at four primary healthcare centers in the city of Barcelona, were included. Each patient underwent morning and night home blood pressure self-monitoring with readings in triplicate for three consecutive days, followed by 24-h ambulatory blood pressure monitoring. The normality cut-off point value for home blood pressure self-monitoring and daytime ambulatory blood pressure monitoring was 135/85 mmHg.

RESULTS

Sixty-three patients were diagnosed with white-coat hypertension with home blood pressure self-monitoring (34.8%; 95% confidence interval: 27.9-42.2) and 74 with ambulatory blood pressure monitoring (41.6%; 95% confidence interval: 33.7-48.4). No statistically significant differences were observed between home blood pressure self-monitoring values and those of diurnal ambulatory blood pressure monitoring [137.4 (14.3)/82.1 (8.3) mmHg vs. 134.8 (11.3)/81.3 (9.5) mmHg]. Home blood pressure self-monitoring diagnostic performance parameters were sensitivity 50.0% (95% confidence interval: 38.3-61.7), specificity 75.7% (95% confidence interval: 66.3-83.2), positive and negative predictive values 58.7% (95% confidence interval: 45.6-70.8) and 68.6% (95% confidence interval: 59.4-76.7), respectively, and positive and negative probability coefficients 2.05 and 0.66, respectively. Analysis of different normality cut-off points using a receiver operating characteristic curve failed to produce significant improvement in the diagnostic performance of home blood pressure self-monitoring.

CONCLUSIONS

The diagnostic accuracy of a 3-day home blood pressure self-monitoring reading program in white-coat hypertension was poor. Ambulatory blood pressure monitoring continues to be the test of choice for this indication.

Glucose metabolism in patients with essential hypertension

PURPOSE

Arterial hypertension is an insulin-resistant condition that has been associated with an increased incidence of diabetes. We assessed the prevalence of glucose abnormalities in a population of patients with essential hypertension.

METHODS

In this cross-sectional study, 420 consecutively referred essential hypertensive patients were studied at 16 hypertension clinics in university and community hospitals of Spain. Fasting and 2-hour plasma glucose and insulin levels were determined in nondiabetic patients.

RESULTS

An abnormal glucose metabolism was diagnosed in 68.5% (95% confidence interval [CI], 63.7%-72.9%) of the patients. Isolated insulin resistance, defined by a homeostasis model assessment-estimated insulin resistance (HOMA-IR) equal to or above 3.8, was shown in 9.3% (95% CI, 6.7%-12.5%); impaired fasting glucose in 11.2% (95% CI, 8.6%-14.7%); impaired glucose tolerance in 22.5% (95% CI, 18.5%-26.9%); silent undiagnosed type 2 diabetes in 11.5% (95% CI, 8.6%-14.5%); and known diabetes mellitus in 13.9% (95% CI, 10.4%-17.2%) of the patients. According to the European Group for the Study of Insulin Resistance and the Adult Treatment Program III criteria, the metabolic syndrome was diagnosed in 41.5% (95% CI, 35.9%-47.3%) and 47.9% (95% CI, 43.1%-52.8%) of the patients, respectively. The prevalence of left ventricular hypertrophy (defined by a left ventricular mass index [LVMI] >125 g/m2 was 44.2%. The relation between HOMA-IR and LVMI was statistically nonsignificant, and the LVMI values in the HOMA-IR quartiles were similar. Only 27 patients (6.4%) showed good control of cardiovascular risk factors. In most patients (273, 65%; 95% CI, 60.3%-69.4%) 2 or more cardiovascular risk factors were identified as not being under control.

CONCLUSIONS

Two thirds of the patients attending hypertension clinics with essential hypertension show an abnormal glucose metabolism. The metabolic syndrome can be identified in a substantial number of these patients, and 2 or more cardiovascular risk factors are not controlled in the majority of patients.

Prevalence and determinants of isolated clinic hypertension in the Finnish population: the Finn-HOME study

BACKGROUND

Previous studies performed in selected hypertensive subjects have reported several possible determinants of isolated clinic hypertension (ICH). The purpose of this study was to assess the prevalence and determinants of ICH in a randomly selected nationwide population.

METHODS

We studied a representative sample of the general adult population (1440 45-74-year-old subjects) in Finland not treated for hypertension. The subjects were drawn from the participants of a multidisciplinary epidemiological survey, the Health 2000 Study. Subjects included in the study underwent a clinical interview, determination of serum lipids and glucose, measurement of clinic and home blood pressure (BP), and psychometric tests for psychological distress, hypochondriasis, depression, and alexithymia. The diagnosis of ICH was based on a clinic BP of 140/90 mmHg or greater and a home BP less than 135/85 mmHg.

RESULTS

The prevalence of ICH in the untreated Finnish adult population was 15.6 and 37.5% among untreated clinic hypertensive individuals. In a multivariate logistic regression analysis, ICH was associated with mildly elevated systolic and diastolic BP, lower body mass index (BMI), and non-smoking status. Subjects with ICH represent an intermediate group between the normotensive and sustained hypertensive individuals where cardiovascular risk is concerned (age, BP, diabetes prevalence, lipid profile, and BMI).

CONCLUSION

ICH is a common phenomenon in the general population. Non-smoking individuals with mildly elevated BP and low BMI have a higher risk of ICH. Physicians should disassociate the diagnosis of ICH from any psychosocial disorders, but should remember that patients with ICH have an increased risk of cardiovascular disease.

Medición de la presión arterial en el domicilio

Measurement of blood pressure (BP) by the own patient at home has become a popular procedure. Both a great offer of simple electronic devices and publication of multiple studies supporting its usefulness for the diagnosis and control of hypertension have contributed to this fact. In fact, this technique has various advantages over the conventional clinical measurement such as a higher reproducibility, better representation of the usual BP profile of the patient, greater correlation with target organs damage and greater morbimortality predictive value. Besides, there is a potential benefit on the control of patients under antihypertensives and, maybe, a reduction in health expenses at long-term follow-up. Currently, the main hypertension societies recommend the home measurement of BP in some clinical situations. However, it cannot be considered an alternative to the clinical measurement but rather a complementary technique in the evaluation of the hypertensive patient. Here we review the indications and limitations of this procedure in clinical practice.

Does the white-coat effect in people of African and South Asian descent differ from that in White people of European origin? A systematic review and meta-analysis

OBJECTIVE

To assess whether the white-coat effect in people of African (Blacks) and South Asian descent differs from that of people of European origin (Whites), and if so, whether this explains demonstrated ethnic variations in blood pressure.

METHODS

A systematic literature review was carried out using Medline 1966-2003, Embase 1980-2003, and citations from references. The meta-analysis was performed using the Cochrane review manager software (RevMan version 4.2; Oxford, UK).

RESULTS

Eight studies were examined, four studies from the UK and four from the USA. The mean systolic and diastolic white-coat effect was similar in Blacks and Whites. The weighted mean difference in systolic white-coat effect was 0.31 [confidence interval 95% (CI)=-1.96, 2.57; P=0.79] and in diastolic white-coat effect was 0.18 (95% CI=-1.70, 1.35; P=0.82). Two studies reported on South Asians. Both systolic and diastolic white-coat effect was significantly lower in South Asians than in Whites; the weighted mean difference in systolic white-coat effect was -8.90 (95% CI=-13.04, -4.76; P<0.0001) and in diastolic white-coat effect was -4.66 (95% CI=-7.29, -2.03; P<0.0001).

CONCLUSION

The blood pressure differences between Blacks and Whites are unlikely to be a result of variations in white-coat effect. In contrast, the slightly lower clinic blood pressure in some South Asian populations such as Bangladeshis might be partly caused by a low white-coat effect but more studies are needed in this subject.

[Effectiveness of self-monitoring of blood pressure in white coat hypertension diagnosis. Rationale and design]

OBJECTIVE

To assess the effectiveness of blood pressure self-monitoring at home in front of 24-h blood pressure ambulatory measurement in isolated clinical hypertension diagnosis.

DESIGN

Comparative study of repeated measurements of self-monitoring home BP and 24-h ambulatory BP measurement in a hypertensive patients sample. SETTING AND SUBJECTS TO STUDY: Mild-moderate essential hypertensive patients newly diagnosed or previously diagnosed in which suspect isolated clinical hypertension (BP>140/90 mm Hg in clinical setting repeatedly). It needs a sample of 182 hypertensive patients seen at urban primary health care.

PRINCIPAL MEASUREMENTS

We compute the isolated clinical hypertension prevalence, the sensibility, specificity and positive and negative predictive values, with 95% confidence intervals.

DISCUSSION

Prove the effectiveness of blood pressure self-monitoring at home in insolated clinical hypertension diagnosis, can involve an important cost saving for health care system as in hypertensive patient management (medicines and office visits), as in diagnosis equipment.

White-coat hypertension: a clinical review

White-coat hypertension (WCHT), also called 'isolated office or clinic hypertension', is defined as the occurrence of blood pressure (BP) values higher than normal when measured in the medical environment, but within the normal range during daily life, usually defined as average daytime ambulatory BP (ABP) or home BP values (<135 mm Hg systolic and <85 mm Hg diastolic). The prevalence of WCHT varies from 15% to over 50% of all patients with mildly elevated office BP (OBP) values. In untreated hypertensive patients, the probability of WCHT especially increases with female gender and a mildly elevated OBP level. The value of other possible determinants such as (non) smoking status, duration of hypertension, left ventricular mass, number of OBP measurements, educational level, etc. is less consistently shown. Although, for various reasons, studies evaluating the long-term effects of WCHT are not always easy to interpret, most data indicate that persons with WCHT have a worse or equal cardiovascular prognosis than normotensives, but a better one than those with sustained hypertension. WCHT is sometimes considered a prehypertensive state, but data on the long-term evolution of subjects with WCHT are scarce. Patients with WCHT and a high cardiovascular risk or proven target organ damage should be pharmacologically treated. Subjects with uncomplicated WCHT should probably not receive medical therapy, but a close follow-up, including regular assessment of other risk factors and measurement of OBP (every 6 months) and ABP (every 1 or 2 years), is warranted.

White Coat Hypertension in Patients With Obstructive Sleep Apnea-Hypopnea Syndrome

BACKGROUND

The strength of the association between obstructive sleep apnea-hypopnea syndrome (OSAHS) and systemic hypertension could be affected by methodologic problems in the definition of hypertension.

STUDY OBJECTIVES

To determine the frequency of white coat hypertension (WCH) in patients with OSAHS, and to analyze the characteristics of patients with OSASH and WCH.

PATIENTS AND INTERVENTIONS

Ninety-nine consecutive patients with OSAHS and 20 healthy control subjects were included into the study. Twenty-four-hour ambulatory BP monitoring (ABPM) and urinary catecholamines were determined simultaneously with the polysomnographic study. Arterial blood gases and lung volumes were also measured.

RESULTS

Office hypertension was diagnosed in 45 patients, while the control group included 54 normotensive patients with OSAHS. After ABPM, hypertension was confirmed in 30 patients with OSAHS and office hypertension. WCH was diagnosed in the remaining 15 patients (33%). Patients with WCH presented higher values of sleep onset latency and wake after sleep onset than normotensive and sustained hypertensive patients. No other differences in sleep parameters, function tests, or urinary catecholamines were found between the OSAHS groups.

CONCLUSION

The results indicate that WCH is a frequent phenomenon in patients with OSAHS, and that it is not predictable by clinical variables.

Microalbuminuria and all-cause mortality in treated hypertensive individuals: does sex matter? The Nord-Trøndelag Health Study (HUNT), Norway

BACKGROUND

In hypertensive individuals, few prospective studies are available in which the association between microalbuminuria (MA) and all-cause mortality in the 2 sexes have been studied within the same population.

METHODS AND RESULTS

We conducted a 4.3-year follow-up of 2307 men and 3062 women (> or =20 years old) with self-reported treated hypertension, all identified in the Nord-Trøndelag Health Study (HUNT), Norway, 1995 to 1997 (n=65 258). The main outcome measures were relative risk (RR) of all-cause mortality according to increasing albuminuria, defined at different levels of albumin-to-creatinine ratio (ACR). There was a consistent positive association between increasing ACR and all-cause mortality in men. The adjusted RR for ACR in the fourth quartile (> or =1.70 mg/mmol) was 1.6 (95% CI, 1.0 to 2.6), compared with ACR in the first quartile (<0.55 mg/mmol). The corresponding RR in women was 1.5 (95% CI, 0.8 to 3.1). We found a positive association between mortality and increasing number of urine samples with ACR above different cutoff levels, especially in men. In 3 urine samples, the lowest ACR level associated with mortality in men was 0.86 mg/mmol, RR 1.6 (95% CI, 1.1 to 2.4). The sex differences persisted after exclusion of those who died during the first year of follow-up, those with hypertension not treated optimally, and those with known cardiovascular disease.

CONCLUSIONS

The association between ACR and all-cause mortality was stronger in treated hypertensive men than in women. The persistent sex differences indicate that hypertensive women tolerate MA better than men and that MA in women should be interpreted differently than in men.

Determinants of the White‐Coat Effect in Normotensives and Never‐Treated Mild Hypertensives

The prognostic significance of the white-coat effect (WCE) is unclear. Knowledge of the predictors of the WCE may help illuminate the clinical significance of this phenomenon. The purpose of this study was to (i) compare characteristics of subjects demonstrating a WCE, those not demonstrating a WCE, and those demonstrating a reverse WCE and (ii) determine clinical features that may influence the size of the WCE. Forty-one subjects with normotension or mild hypertension who had never been treated with antihypertensive medications were recruited for the study. All subjects underwent a battery of anthropometrical measurements and clinic blood pressure (BP) measurements. To calculate arterial compliance, impedance cardiography was used to measure resting stroke volume in each subject. All subjects performed a laboratory mental stress protocol to determine the size of the BP reactivity. Ambulatory blood pressure (ABP) profiles were studied in each subject with the use of an oscillometric ABP recorder. White-coat effect was determined by subtracting the awake period of the ambulatory systolic blood pressure (SBP) from the clinical SBP. Subjects were grouped according to the size of their WCE. Those who showed a WCE of 5 mmHg and above were assigned to the WCE group; those who showed a WCE of between -5 and 5 mmHg were assigned to the no white coat effect (NWCE) group; those who exhibited a WCE of -5 mmHg and lower were assigned to the reverse white-coat effect (RWCE) group. Subjects with a positive WCE had significantly higher body mass index (BMI) than those without a WCE and those with a RWCE. The WCE group had significantly higher clinic SBP and heart rate (HR) than the RWCE group. Arterial compliance was significantly lower in the WCE group as compared to the NWCE group and the RWCE group. The three groups had comparable ABP profiles. In terms of BP variability, the increase in SBP in response to mental stress did not differ among the three study groups nor did the 24-hour and awake BP variability. For the sample as a whole, clinic HR and clinic-ambulatory SBP difference were higher and arterial compliance were lower in women than in men. Furthermore, clinic SBP significantly correlated with the systolic WCE (r = 0.40, P = 0.009). When men and women were analyzed separately, the correlation between clinic SBP and the systolic WCE was significant in women (r = 0.63, P = 0.001) but not in men (P = 0.95). Multiple linear regression showed that sex (P = 0.013) and clinical SBP (P = 0.003) were the only two variables that significantly influenced the systolic WCE. These two variables together accounted for 29% of the variation in the systolic WCE. In conclusion sex and clinic BP are two major determinants of the WCE. The results of this study indicate that WCE is not related to higher stress reactivity or higher BP variability.

Circulating homocysteine levels in sustained and white coat hypertension

Although white coat hypertension has been widely studied in the last years, its risk profile is not yet completely clear. The aim of this study was to evaluate circulating homocysteine levels, an emerging cardiovascular risk factor, in subjects with white coat and sustained hypertension. We selected 31 sustained hypertensive subjects, 31 white coat hypertensive subjects and 31 normotensive subjects matched for age, gender, body mass index and occupation. Women were also matched for menopausal status. Subjects with smoking habit, dyslipidaemia and diabetes mellitus were excluded from the study. White coat hypertension was defined as clinical hypertension and daytime ambulatory blood pressure <135/85 mmHg. Blood samples were drawn after a fasting period of 12 h for routine laboratory tests and homocysteine determination. Homocysteine levels were evaluated by fluorescence polarization immunoassay. Creatinine, glucose, cholesterol and triglycerides were not different among the groups. White coat hypertensive subjects had significantly lower homocysteine levels than sustained hypertensive patients (8.2+/-2.0 vs 12.6+/-3.9 micromol/l, P=0.0003). No significant difference was observed between white coat hypertensive and normotensive subjects regarding this parameter (8.2+/-2.0 vs 7.6+/-1.9 micromol/l, P=0.9). In conclusion, our data show that middle-aged white coat hypertensive subjects without other cardiovascular risk factors have lower circulating homocysteine levels than sustained hypertensive patients suggesting that they are at lower cardiovascular risk.