Blood pressure dipping is reproducible in clinical practice

Circadian blood pressure profile and blood pressure changes following oral appliance therapy for obstructive sleep apnoea

OBJECTIVES

Oral appliance therapy for obstructive sleep apnoea (OSA) reduces blood pressure (BP) but there is little information on relationship to circadian BP pattern (nocturnal BP dipping or non-dipping). The aims of this study were to determine whether nocturnal dipping pattern influences BP changes following oral appliance therapy, and to determine the effect of oral appliance therapy on circadian BP pattern.

METHODS

Participants in two randomized trials of oral appliance therapy (1-2 months) with 24-h ambulatory BP monitoring (ABPM) data were included (N = 152). Nocturnal BP Dippers (nocturnal/diurnal SBP ratio <0.9) and non-dippers were compared for BP changes following oral appliance therapy and the effect of oral appliance therapy on nocturnal BP dipping was assessed.

RESULTS

Of 152 participants, 64.5% were dippers. Dippers were on average younger and less likely to be hypertensive (42 vs. 82.7%, P < 0.001). Nondippers showed greater reduction in nocturnal BP measures, related to higher BP measures at baseline. There was no difference in the relationship between treatment effectiveness and BP changes between groups. Oral appliance therapy converted only 23% of baseline non-dippers to a nocturnal dipping profile.

CONCLUSION

Baseline circadian BP profile influenced the BP response to oral appliance therapy, largely because of higher baseline BP in the non-dipper subgroup. Oral appliance therapy did not convert OSA patients to a more favourable circadian BP profile. Further work is required to understand the effect of oral appliance therapy on circadian BP profile and of the individuals who will receive cardiovascular benefit from oral appliance therapy.

Reproducibility study of nocturnal blood pressure dipping in patients with high cardiovascular risk

It has been shown that in most people there is a physiological reduction in blood pressure during nighttime sleep, it falling by approximately 10% compared to daytime values (dippers). On the other hand, in some people, there is no nighttime reduction (non‐dippers). Various studies have found an association between being a non‐dipper and a higher risk of cardiovascular disease, but few have assessed whether the nocturnal pattern is maintained over time. From the database of the TAHPS study, data were available on 225 patients, each of whom underwent 24‐hour ambulatory blood pressure monitoring (ABPM) on four occasions over a period of 5 months. We studied the reproducibility of the nocturnal BP dipping pattern with mixed linear analysis and also calculated the concordance in the classification of patients as dippers or non‐dippers. The intraclass correlation coefficients between the different ABPM recordings were 0.482 and 0.467 for systolic and diastolic blood pressure, respectively. Two‐thirds (67%) and 70% of the patients classified, respectively, as dippers or non‐dippers based on systolic and diastolic blood pressure readings in the first ABPM recording were found to have the same classification based on the subsequent recordings. We conclude that the reproducibility of nocturnal dipping patterns and concordance of dipper vs non‐dipper status in individual patients is modest and therefore that we should be cautious about recommending treatments or interventions based on these patterns.

Poor sleep quality is responsible for the nondipper pattern in hypertensive but not in normotensive chronic kidney disease patients

AIM

This study was designed to evaluate the relationship between sleep quality and hypertension and to determine if there was an association between nondipper blood pressure (BP) and sleep quality in chronic kidney disease (CKD) patients.

METHODS

A total of 775 pre-dialysis CKD patients (314 normal BP patients, 461 hypertension patients) defined as dippers or nondippers by ambulatory BP monitoring were recruited for this study. Demographics and clinical correlates were collected, including body mass index, estimated glomerular filtration rate (eGFR) and other measures. Sleep quality was measured using the Pittsburgh Sleep Quality Index (PSQI).

RESULTS

A total of 185 (58.9%) patients with normal BP and 341 (74.0%) hypertensive patients had a nondipper BP pattern. The hypertension group had a higher prevalence of the nondipper BP pattern, smoking, alcohol intake and diabetes mellitus (DM) and lower eGFR levels and poorer sleep quality than the normal BP group. Patients with the nondipper BP pattern had lower haemoglobin, worse renal function and poorer sleep quality when compared with hypertensive CKD patients with the dipping BP pattern. PSQI scores were significantly associated with the rate of nocturnal BP decline (P < 0.05) in the hypertension group but not in the normal BP group. Poor sleep quality was an independent factor affecting BP pattern in hypertensive CKD patients using multivariate linear and logistic regression analyses. There was no association between sleep quality and hypertension in CKD patients after multivariate logistic regression analyses.

CONCLUSION

Poor sleep quality, which is commonly observed in pre-dialysis CKD patients, is an independent associated factor of the nondipper BP pattern in hypertensive CKD patients. No association was found between poor sleep and nondipper BP in normotensive patients.

High trait rumination is associated with blunted nighttime diastolic blood pressure dipping

Background

Blunted blood pressure (BP) dipping during nighttime sleep has been associated with an increased risk of cardiovascular events. Psychological traits have been associated with prolonged cardiovascular activation and a lack of cardiovascular recovery. This activation may extend into nighttime sleep and reduce BP dipping.

Purpose

This study aims to evaluate the association between trait rumination and nighttime BP dipping.

Methods

Sixty women scoring either high or low on trait rumination underwent one 24-h ambulatory BP monitoring session. Self-reported wake and sleep times were used to calculate nighttime BP.

Results

High trait rumination was associated with less diastolic blood pressure (DBP) dipping relative to low trait rumination. Awake ambulatory BP, asleep systolic blood pressure (SBP) and DBP, and asleep SBP dipping were not associated with trait rumination.

Conclusions

In a sample of young women, high trait rumination was associated with less DBP dipping, suggesting that it may be associated with prolonged cardiovascular activation that extends into nighttime sleep, blunting BP dipping.

Differential expression of vascular smooth muscle-modulating microRNAs in human peripheral blood mononuclear cells: novel targets in essential hypertension

Vascular smooth muscle cell (VSMC) phenotypic plasticity has a critical role in the pathophysiology of arterial remodeling in essential hypertension. MicroRNAs are emerging as potential biomarkers and therapeutic targets in cardiovascular disease. We assessed the expression levels of the microRNAs miR-143, miR-145, miR-21, miR-133 and miR-1, which are implicated in VSMC phenotypic modulation, in 60 patients with essential hypertension and 29 healthy individuals. All patients underwent 24-h ambulatory blood pressure (BP) monitoring. MicroRNA levels in peripheral blood mononuclear cells were quantified by real-time reverse transcription polymerase chain reaction. Hypertensive patients showed lower miR-143 (2.20±0.25 versus 4.19±0.57, P<0.001), miR-145 (13.51±1.73 versus 22.38±3.31, P=0.010) and miR-133 (8.15±1.32 versus 37.03±8.18, P<0.001) and higher miR-21 (3.08±0.32 versus 2.06±0.31, P=0.048) and miR-1 (33.94±5.19 versus 12.35±2.13 P=0.006) expression levels compared with controls. In hypertensive patients, we observed correlations of miR-143 (r = -0.380, P=0.003), miR-145 (r=-0.405, P=0.001), miR-21 (r=-0.486, P<0.001) and miR-133 (r=0.479, P<0.001) expression levels with 24-h diastolic BP. Furthermore, we observed correlations of miR-21 (r=-0.291, P=0.024), miR-1 (r=-0.312, P=0.015) and miR-133 (r=0.310, P=0.016) levels with the dipping status. Associations of miR-143 (r=-0.292, P=0.025), miR-145 (r=-0.399, P=0.002), miR-21 (r=-0.343, P=0.008) and miR-133 (r=0.370, P=0.004) levels with 24-h mean pulse pressure were also found. Our data provide important evidence that VSMC-modulating microRNAs are closely related to essential hypertension in humans and they may represent potential therapeutic targets in essential hypertension.

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

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

Step count is associated with lower nighttime systolic blood pressure and increased dipping

BACKGROUND

Higher nighttime blood pressure (BP) and the loss of nocturnal dipping of BP are associated with an increased risk for cardiovascular events. However, the determinants of the loss of nocturnal BP dipping are only beginning to be understood. We investigated whether different indicators of physical activity were associated with the loss of nocturnal dipping of BP.

METHODS

We conducted a cross-sectional study of 103 patients referred for 24-hour ambulatory monitoring of BP. We measured these patients' step count (SC), active energy expenditure (AEE), and total energy expenditure simultaneously, using actigraphs.

RESULTS

In our study population of 103 patients, most of whom were hypertensive, SC and AEE were associated with nighttime systolic BP in univariate (SC, r = -0.28, P < 0.01; AEE, r = -0.20, P = 0.046) and multivariate linear regression analyses (SC, coefficient beta = -5.37, P < 0.001; AEE, coefficient beta = -0.24, P < 0.01). Step count was associated with both systolic (r = 0.23, P = 0.018) and diastolic (r = 0.20, P = 0.045) BP dipping. Nighttime systolic BP decreased progressively across the categories of sedentary, moderately active, and active participants (125mm Hg, 116mm Hg, 112mm Hg, respectively; P = 0.002). The degree of BP dipping of BP increased progressively across the same three categories of activity (respectively 8.9%, 14.6%, and 18.6%, P = 0.002, for systolic BP and respectively 12.8%, 18.1%, and 22.2%, P = 0.006, for diastolic BP).

CONCLUSIONS

Step count is continuously associated with nighttime systolic BP and with the degree of BP dipping independently of 24-hour mean BP. The combined use of an actigraph for measuring indicators of physical activity and a device for 24-hour measurement of ambulatory BP may help identify patients at increased risk for cardiovascular events in whom increased physical activity toward higher target levels may be recommended.

Short-term reproducibility of ambulatory blood pressure monitoring in autosomal dominant polycystic kidney disease

BACKGROUND AND OBJECTIVES

Nondipping, defined as a less than 10% decline in Night:Day (N:D) ratio of blood pressure using 24 h ambulatory blood pressure monitoring, is associated with poor cardiovascular outcomes. However, its reproducibility has been questioned in autosomal dominant polycystic kidney disease.

MATERIALS AND METHODS

Twenty-five of 29 recruited hypertensive or prehypertensive patients with autosomal dominant polycystic kidney disease completed ambulatory blood pressure monitoring on two occasions, 7-15 days apart, on a stable antihypertensive regimen. Daytime and night-time were defined as 6:00-21:59 h and 22:00-5:59 h, respectively. Correlation and concordance coefficients for systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate were determined based on N:D and Asleep:Awake (A:A) ratios. Consistency of dipping was assessed by using Cohen's Kappa statistics.

RESULTS

Mean (±standard deviation) for age, estimated glomerular filtration rate, differences in daytime and night-time SBP and DBP were 43.12 years (8.55 years), 63.1 ml/min (20.5 ml/min), 11.74 mmHg (8.2 mmHg), and 10.82 mmHg (6.4 mmHg), respectively. Seventeen of 25 (68%) and 18 of 25 (72%) participants maintained the same dipping category based on D:N or A:A separation. Cohen's Kappa was 0.34 for D:N ratio and 0.38 for A:A ratio. Correlation and concordance coefficients were 0.89 and 0.88 for daytime SBP, 0.91 and 0.91 for daytime DBP, 0.79 and 0.78 for night-time SBP, 0.81 and 0.80 for night-time DBP, 0.58 and 0.56 for N:D ratio of SBP, and 0.56 and 0.53 for N:D ratio of DBP. Coefficients for A:A ratio were almost identical to N:D values except for A:A ratios of SBP (0.69 and 0.67) and DBP (0.48 and 0.45).

CONCLUSION

Repeated measures of SBP and DBP, 7-15 days apart, are highly correlative and concordant in the studied population, but nondipping, even though predominant, was found to be modestly reproducible.

Twenty-four-hour ambulatory blood pressure measurement in clinical practice and research: a critical review of a technique in need of implementation

This review presents evidence that ambulatory blood pressure measurement (ABPM) should be used more widely in clinical practice and hypertension research. The technique, which should be mandatory in trials of antihypertensive drugs, is not being used in all studies of antihypertensive drug efficacy. ABPM is also being under-used in outcome studies. The failure to implement ABPM in primary care and hypertension research is impeding patient management and scientific advancement. ABPM offers so many advantages in assessing the efficacy of blood pressure (BP)-lowering drugs that it should be mandatory in pharmacological trials. Likewise, the technique provides a means of achieving BP control in clinical practice, which is essential if we are to halt the epidemic of the cardiovascular consequences of hypertension. However, if ABPM is to be implemented for these purposes, certain requirements will need to be fulfilled. These include the availability of accurate, patient-friendly and inexpensive devices; standardization of the presentation and plotting of data with summary statistics for day-to-day practice; provision of comprehensive data analysis for research; an interpretative report to facilitate use in busy clinical practice; a trend report to demonstrate efficacy or otherwise of treatment in clinical practice and online transmission of data to provide immediate real-time data analysis. The reasons why ABPM is not being implemented are reviewed, and proposals are made to make the technique more acceptable.

The relationship of oxidative stress and cholesterol with dipping status before and after aerobic exercise training

OBJECTIVE

The purpose of this study was to examine the effects of aerobic exercise training (AEXT) on dipping status in pre-hypertensive and stage-1 hypertensive individuals. A secondary purpose was to evaluate whether AEXT alters oxidative stress and endothelial biomarkers correlated to dipping status.

METHODS

Twenty-three subjects underwent 24-h ambulatory blood pressure monitoring at baseline and after 6 months of AEXT. AEXT consisted of training at 70% VO(2max) 3 days/week for 6 months. Total cholesterol, high-density lipoprotein-cholesterol, low-density lipoprotein (LDL)-cholesterol, oxidized LDL (ox-LDL), triglycerides, urinary and plasma nitric oxide end-products, superoxide dismutase and 8-iso-PGF(2alpha) were measured before and after AEXT. Statistically, ANOVA and linear regression were used.

RESULTS

Before and after AEXT, there were no significant differences between dippers and non-dippers in any of the biomarkers except for total cholesterol following AEXT. In a sub-analysis following AEXT, 14 subjects retained their original dipping status, five subjects changed from dippers to non-dippers and four subjects changed from non-dippers to dippers. Significant differences existed between these groups in changes in total and LDL-cholesterol, ox-LDL, 8-iso-PGF(2alpha) and % Dip.

CONCLUSIONS

Changes in cholesterol levels but not oxidative stress or endothelial biomarkers were related to changes in BP variables following AEXT in dippers and non-dippers.

The reproducibility of ethnic differences in the proportional awake-sleep blood pressure decline among women

A growing body of evidence indicates that African Americans (AA), on average, have a smaller proportional decline in blood pressure (BP) from waking to sleep than European Americans (EA), but this difference is largely based on correlational data from a single assessment day. The persistence of this difference over repeated sampling is not well established. The purpose of this study was to evaluate whether ethnic differences in the awake-sleep BP decline between AA and EA persisted over three monthly assessments. The subjects were 47 AA (age = 39.7 +/- 8.7) and 92 EA (age = 37.4 +/- 9.2) normotensive women. Subjects had 24-h ambulatory BP monitoring done on midweek workdays at 1-month intervals for three consecutive months. The proportional decline in BP was calculated as follows: (average awake - average sleep)/average sleep. The persistence of ethnic differences was evaluated using repeated-measures ANCOVA and by examining Bland-Altman plots. The ANCOVA results revealed that overall, the proportional decline of AA women was less than that of EA women for both SBP (P < 0.038) and DBP (P < 0.083), consistent with previous research, and that there were also no significant ethnic differences by monthly assessment. Bland-Altman plots revealed that overall and by ethnicity, the proportional decline in BP among individual subjects over the 3 months was also reproducible. These results suggest that the ethnic difference in awake-sleep BP between AA and EA women persists over time and that the awake-sleep decline in BP among individuals, whether AA or EA, is also reproducible.

Everyday discrimination and nocturnal blood pressure dipping in black and white americans

OBJECTIVE

To investigate whether an association exists between experiences of everyday discrimination and blood pressure (BP) dipping in a biracial sample of black and white adults. Attenuated nocturnal BP dipping is closely linked to cardiovascular morbidity and mortality. Self-reported experiences of everyday discrimination have also been associated with negative cardiovascular health outcomes.

METHODS

Seventy-eight hypertensive and normotensive women and men (n = 30 black and 48 white) reported on their experiences of everyday discrimination (Everyday Discrimination Scale) and underwent two separate 24-hour ambulatory BP monitoring (ABPM) sessions approximately 1 week apart.

RESULTS

Correlation analysis revealed that higher endorsement of everyday discrimination was significantly associated with less diastolic BP (DBP) and systolic BP (SBP) dipping (p < .05). Subsequent hierarchical regression analyses indicated that everyday discrimination explained 8% to 11% of the variance in SBP and DBP dipping above and beyond other demographic and life-style-related factors, including race, age, 24-hour BP, body mass index, and current socioeconomic status. The relationship between discrimination and dipping was significantly stronger on the second night of monitoring. Finally, analyses revealed that everyday discrimination mediated the relationship between race and BP dipping.

CONCLUSIONS

These findings suggest that experiences of everyday discrimination are associated with less nocturnal SBP and DBP dipping above and beyond the effect of known covariates. The use of multiple ABPM sessions may facilitate the detection of relationships between psychological variables and BP dipping.

Sleep quality among relatively younger patients with initial diagnosis of hypertension: Dippers versus non‐dippers

BACKGROUND

Sleep is a basic physiological process. Normal sleep yields decrease in sympathetic activity, blood pressure (BP) and heart rate. Those, who do not have expected decrease in their BP are considered "non-dippers". We aimed to determine if there was any association between the non-dipping status and sleep quality, designed a cross-sectional study, and enrolled and evaluated the sleep quality of relatively young patients with an initial diagnosis of hypertension.

METHODS

Seventy-five consecutive patients, diagnosed to have stage 1 hypertension by their primary physicians, were referred to our study. Patients had newly diagnosed with stage 1 hypertension. Patients with a prior use of any anti-hypertensive medication were not included. Eligible patients underwent the Pittsburgh Sleep Quality Index (PSQI), which has an established role in evaluating sleep disturbances. All patients underwent ambulatory BP monitoring.

RESULTS

There were 42 non-dipper patients (mean age = 47.5+/-11.9 years, 24 male/18 female), as a definition, 31 dipper hypertensive patients (mean age = 48.5+/-12.8 years, 21 male/10 female) and two with white coat hypertension. Daytime systolic and diastolic mean BPs were not significantly different between the two groups. Night-time mean systolic and diastolic BPs were significantly higher in non-dippers compared with dippers. PSQI scores, globally, were significantly higher in non-dippers compared with dippers. Total PSQI score was not correlated with body mass index. It was noticed that, individually, sleep quality, sleep efficiency and sleep disturbance scores were significantly higher in non-dippers. Being a poor sleeper in terms of high PSQI score (total score>5) was associated with 2.955-fold increased risk of being a non-dipper (95% confidence interval 1.127-7.747).

CONCLUSION

We showed that the risk of having non-dipping hypertension, a risk factor for poor cardiovascular outcomes among hypertensive individuals, was tripled (odds ratios) among poor sleepers. We think that evaluating sleeping status and sleep quality among the hypertensive population may help unmask non-dipper hypertension, enabling physicians to treat appropriately.

Socioeconomic and psychosocial factors mediate race differences in nocturnal blood pressure dipping

BACKGROUND

Reduced nocturnal blood pressure (BP) dipping is more prevalent among blacks living in the United States than whites and is associated with increased target organ damage and cardiovascular risk. The primary aim of this study was to determine whether socioeconomic and psychosocial factors help to explain racial differences in dipping. In order to address the limited reproducibility of dipping measures, we investigated this question in a sample of participants who underwent multiple ambulatory BP monitoring (ABPM) sessions.

METHODS

The study sample included 171 black and white normotensive and mildly hypertensive participants who underwent three ABPM sessions, each 1 month apart, and completed a battery of questionnaires to assess socioeconomic and psychosocial factors.

RESULTS

As expected, blacks showed less dipping than whites, after adjusting for age, sex, body mass index (BMI), and mean 24-h BP level (mean difference = 3.3%, P = 0.002). Dipping was related to several of the socioeconomic and psychosocial factors examined, with higher education and income, being married, and higher perceived social support, each associated with a larger dipping percentage. Of these, marital status and education were independently associated with dipping and together accounted for 36% of the effect of race on dipping.

CONCLUSIONS

We identified a number of socioeconomic and psychosocial correlates of BP dipping and found that reduced dipping among blacks vs. whites is partially explained by marital status (being unmarried) and lower education among blacks. We also present results suggesting that repeated ABPM may facilitate the detection of associations between dipping and other variables.

Different classifications of nocturnal blood pressure dipping affect the prevalence of dippers and nondippers and the relation with target-organ damage

OBJECTIVE

We assessed how different definitions of the awake and asleep periods and use of various blood pressure (BP) indices affect the extent of the nocturnal BP dip, the prevalence of dippers and nondippers, their respective reproducibilities and the relation of nondipping with target-organ damage.

METHODS

We performed 24-h ambulatory BP monitoring twice and determined the left ventricular mass index and urinary albumin excretion as indices of target-organ damage in 150 hypertensive patients (off-medication). Awake and asleep periods were assessed using fixed and diary time methods, covering all readings available (wide) or excluding morning and evening transition hours (narrow). Nondipping (BP dip < 10%) was established for systolic BP and diastolic BP, their combinations (and/or), and mean arterial pressure.

RESULTS

The different awake-asleep definitions caused significant variation in both the extent of the BP dip and the number of dippers and nondippers in comparison with the wide diary definition (i.e. use of actual awake and sleep periods). The prevalences of dippers and nondippers also varied significantly with the BP index. Reproducibility analyses of the BP dip and the dipping status yielded repeatability coefficients (expressed as percentages of nearly maximal variation) between 42.39 and 48.71%, and kappa values between 0.323 and 0.459, respectively. Some classifications, but not all, discriminated significantly between consistent dippers and nondippers in terms of left ventricular mass index or urinary albumin excretion.

CONCLUSIONS

Use of different definitions of awake-asleep and BP indices affects significantly the classification of nocturnal BP dipping and its relation with hypertensive target-organ damage.

Pulse pressure or dipping pattern: which one is a better cardiovascular risk marker in resistant hypertension?

OBJECTIVE

Nocturnal blood pressure (BP) reduction and ambulatory pulse pressure (PP) are well known prognostic markers obtained from ambulatory BP monitoring (ABPM). The aim of this study is to investigate which one of these ABPM parameters is related to high cardiovascular risk profile in resistant hypertension, based on their associations with target organ damage (TOD).

METHODS

Clinical-demographic, laboratory and ABPM variables were recorded in a cross-sectional study involving 907 resistant hypertensive patients. Nocturnal systolic BP reduction and 24-h PP were assessed both as continuous and dichotomized variables (PP at the upper tertile value: 63 mmHg). Statistical analyses included bivariate tests and multivariate logistic regression with each TOD as the dependent variable.

RESULTS

Patients with the nondipping pattern and high 24-h PP shared some characteristics: they were older, had higher prevalence of cerebrovascular disease and nephropathy, higher office and 24-h BP levels, increased serum creatinine and microalbuminuria, and higher left ventricular mass index than their counterparts. Additionally, patients with high PP had a greater prevalence of diabetes and other TOD. In multivariate logistic regression, high PP was independently associated with all TODs even after adjustment for sex, age, BMI, cardiovascular risk factors, 24-h mean arterial pressure and antihypertensive treatment, whereas nondipping pattern was only associated with hypertensive nephropathy. Furthermore, PP was more strongly associated with the number of TOD than the nocturnal systolic blood pressure (SBP) fall.

CONCLUSIONS

In a large group of resistant hypertensive patients, an increased 24-h PP shows a closer correlation with high cardiovascular risk profile than the nocturnal BP reduction.

Early socioeconomic status is associated with adult nighttime blood pressure dipping

OBJECTIVE

To examine the prognostic significance of early socioeconomic status (SES) on 24-hour blood pressure (BP) during early adulthood. Low SES has been related to poor health outcomes, in particular, cardiovascular morbidity and mortality. Recent cross-sectional research has also linked low levels of SES with several cardiovascular risk factors including poor nighttime BP dipping.

METHODS

A total of 174 undergraduate university students whose childhood SES was assessed by highest level of education completed by their parents underwent 24-hour ambulatory BP monitoring.

RESULTS

Initial correlation analyses revealed positive associations between childhood SES and BP dipping, indicating that lower levels of childhood SES were associated with less systolic BP (SBP) (r = .29, p < .01) and diastolic BP (DBP) dipping (r = .38, p < .01). A stepwise multiple regression analyses indicated that childhood SES explained 6.9% of the variance in SBP dipping and 11.5% of the variance in DBP dipping above and beyond other lifestyle-related factors including daytime BP, body mass index, alcohol use, smoking, and current SES.

CONCLUSIONS

These findings suggest that irrespective of adult achievement, childhood SES may have lasting health implications.

Predictors of All-Cause Mortality in Clinical Ambulatory Monitoring

The prognostic value of sleep blood pressure reported by recent studies is variable. Our aim was to examine the relationship of sleep blood pressure, measured by 24-hour ambulatory blood pressure monitoring, with all-cause mortality. We studied a cohort of 3957 patients aged 55+/-16 (58% treated) referred for ambulatory monitoring (1991-2005). Sleep, including daytime sleep, was recorded by diary. Linkage with the national population register identified 303 deaths during 27 750 person-years of follow-up. Hazard ratios (HRs) for mortality in Cox proportional hazards models that included age, sex, hypertension, and diabetes treatment were 1.32 (95% CI: 0.99 to 1.76) for awake hypertension (>or=135/85 mm Hg), and 1.67 (95% CI: 1.25 to 2.23) for sleep hypertension (>or=120/70 mm Hg). By quintile analysis, the upper fifths of systolic and diastolic dipping during sleep were associated with adjusted HRs of 0.58 (95% CI: 0.41 to 0.82) and 0.68 (95% CI: 0.48 to 0.96), respectively. In a model controlling for awake systolic blood pressure, hazards associated with reduced systolic dipping increased from dippers (>10%; HR: 1.0), through nondippers (0% to 9.9%; HR: 1.30; 95% CI: 1.00 to 1.69) to risers (<0%; HR: 1.96; 95% CI: 1.43 to 2.96). Thus, in practice, ambulatory blood pressure predicts mortality significantly better than clinic blood pressure. The availability of blood pressure measures during sleep and, in particular, the pattern of dipping add clinically predictive information and provide further justification for the use of ambulatory monitoring in patient management.

The circadian nuances of hypertension: a reappraisal of 24-h ambulatory blood pressure measurement in clinical practice

Ambulatory blood pressure measurement has been in use in clinical practice for nearly half a century. However, despite the benefits the technique brings to managing patients with hypertension it is much under-used in practice. The purpose of this review is to examine critically the information that can be derived from the technique and to highlight the application of this evidence in clinical practice.

How should patients treated with alpha-blockers be followed? Insights from an ambulatory blood pressure monitoring database

OBJECTIVE

Adrenergic alpha-antagonists have been suggested to confer lesser protection, compared to diuretics, when used as first agents for hypertension. While differences in clinic blood pressure may be partly responsible, this inferiority is unexpected in light of the metabolic advantages of alpha-blockade. The aim of this study was to evaluate the relationship between use of alpha-blockers and blood pressure dipping.

METHODS

A database of a 24-h ambulatory monitoring service was cross-sectionally evaluated for associations between antihypertensives and dipping. There were 681 treated subjects during a 3-year period (age 63 +/- 14, 57% female).

RESULTS

Overall, 78 of 681 treated hypertensive subjects used alpha-blockers (11%). Nine per cent of dippers and 16% of nondippers were treated with alpha-blockade, odds ratio 2.0. Whereas clinic, 24-h, and awake blood pressures were similar in alpha-blocker users and nonusers, sleep blood pressure was significantly higher in the former group. Furthermore, significantly fewer subjects given alpha-blockers had a controlled sleep blood pressure. Among alpha-blocker nonusers sleep blood pressure was the best controlled category, whereas in alpha-blocker users manual blood pressure had the highest rate of control. Generally, accounting for covariates of alpha-blockade (age, gender, diabetes, total number of medications) did not influence the above-mentioned trends. Finally, a limited negative dose-response relationship between alpha-blockade and dipping magnitude was also noticed.

CONCLUSIONS

We found a significant negative association between adrenergic alpha-blockade and the magnitude of sleep-related blood pressure decline. Awaiting results from interventional studies, this may suggest a need to perform ambulatory monitoring in patients given alpha-blocking agents (or at least supine and standing measurements), and may partially clarify the inferiority of doxazosin in the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT).