Changes in home versus clinic blood pressure with antihypertensive treatments: a meta-analysis

Home blood pressure (HBP) monitoring is recommended for assessing the effects of antihypertensive treatment, but it is not clear how the treatment-induced changes in HBP compare with the changes in clinic blood pressure (CBP). We searched PubMed using the terms "home or self-measured blood pressure," and selected articles in which the changes in CBP and HBP (using the upper arm oscillometric method) induced by antihypertensive drugs were presented. We performed a systematic review of 30 articles published before March 2008 that included a total of 6794 subjects. As there was significant heterogeneity in most of the outcomes, a random effects model was used for the meta-analyses. The mean changes (+/-SE) in CBP and HBP (systolic/diastolic) were -15.2+/-0.03/-10.3+/-0.03 mm Hg and -12.2+/-0.04/-8.0+/-0.04 mm Hg respectively, although there were wide varieties of differences in the reduction between HBP and CBP. The reductions in CBP were correlated with those of HBP (systolic BP; r=0.66, B=0.48, diastolic BP; r=0.71, B=0.52, P<0.001). In 7 studies that also included 24-hour BP monitoring, the reduction of HBP was greater than that of 24-hour BP in systolic (HBP; -12.6+/-0.06 mm Hg, 24-hour BP; -11.9+/-0.04 mm Hg, P<0.001). In 5 studies that included daytime and nighttime systolic BP separately, HBP decreased 15% more than daytime ambulatory BP and 30% more than nighttime ambulatory BP. In conclusion, HBP falls approximately 20% less than CBP with antihypertensive treatments. Daytime systolic BP falls 15% less and nighttime systolic BP falls 30% less than home systolic BP.     

Subclinical left ventricular dysfunction in systemic hypertension and the role of 24-hour blood pressure

The relation between blood pressure (BP) and left ventricular (LV) systolic function in systemic hypertension is controversial. We assessed the relation of LV midwall fractional shortening (FS) to 24-hour BP in 1,702 never-treated hypertensive subjects (age 48 +/- 12 years), who underwent 24-hour BP monitoring and echocardiography. Stress-corrected endocardial and midwall FS (the latter calculated taking into account the epicardial migration of midwall during systole) were predicted in hypertensives on the basis of the values observed in 130 healthy normotensives (age 43 +/- 13 years, office BP 126/78 mm Hg). Subjects below the fifth percentile of observed-to-predicted FS had depressed LV function. The use of midwall FS resulted in an increase from 3.5% to 17.5% in the proportion of patients with depressed chamber function. Compared with the group with normal function, subjects with low midwall LV function had similar office systolic BP (155 +/- 21 vs 154 +/- 17 mm Hg), but increased 24-hour systolic BP (140 +/- 17 vs 133 +/- 12 mm Hg, p <0.001). Midwall FS had a closer negative relation to 24-hour systolic BP than to office systolic BP (r = -0.27 vs -0.08, p <0.001), whereas this difference was not apparent for diastolic BP (r = -0.23 vs -0.20). Compared with endocardial FS, midwall FS had a stronger inverse association to LV mass (r = -0.45 vs -0.16, p <0.001). Thus, an increased 24-hour BP load may chronically lead to depressed myocardial function in systemic hypertension in the absence of clinically overt heart disease.     

Effects of age and 24-hour ambulatory blood pressure on rapid left ventricular filling

To determine the associations of age, blood pressure (BP) and cardiac structure with left ventricular (LV) diastolic performance, 47 subjects (21 normotensives and 26 age-matched, previously untreated hypertensives) were studied by 24-hour ambulatory BP monitoring, radionuclide ventriculography and sector-guided M-mode echocardiography. Normotension was defined as an awake ambulatory BP less than 130/80 mm Hg and hypertension as an awake ambulatory BP greater than 135/85 mm Hg. Univariate analyses revealed strong negative correlations of LV filling rate with age (r = -0.67, p less than 0.001), 24-hour systolic or diastolic BP (r = -0.59 for systolic BP and -0.57 for diastolic BP, p less than 0.001 for both) and a modest positive correlation with LV ejection fraction (r = 0.42, p less than 0.05). After multivariate analysis, significant dependencies of both the left atrial index and LV mass index on ambulatory BP were found, which negated the significance of the relation of these 2 cardiac structural variables with LV filling rate. The final regression equation predicted LV filling rate from age, BP and LV ejection fraction. Age was the most important single correlate of LV filling, as evidenced by the 14 of 16 subjects (88%) over the age of 53 years (8 hypertensives, 6 normotensives) who had reduced LV filling rates compared with only 9 of the remaining 31 subjects (29%, all hypertensives) under the age of 53 years with reduced LV filling rates. These data demonstrate that LV filling rate is more dependent upon age and BP than left atrial or LV size.(ABSTRACT TRUNCATED AT 250 WORDS)     

Influence of the arterial blood pressure and nonhemodynamic factors on left ventricular hypertrophy in moderate essential hypertension.

In a group of 36 untreated patients with mild to moderate essential hypertension (office systolic and diastolic blood pressures (BPs) 160 +/- 3.4 and 102 +/- 1.5 mm Hg, respectively), a 24-hour ambulatory BP monitoring and determination of left ventricular (LV) mass index according to the formula of Devereux were performed. After an overnight fast, blood samples were taken for the determination of serum aldosterone, plasma renin activity and serum parathyroid hormone. Urinary catecholamines were sampled for 24 hours. LV mass index (143.7 +/- 8 g/m2) did not correlate significantly either with office systolic or diastolic BP. The correlation of LV mass index with mean 24-hour systolic BP (145 +/- 3 mm Hg) was statistically significant: r = 0.395, p = 0.026. However, the best correlation was obtained with mean 24-hour diastolic BP (90 +/- 3 mm Hg) with r = 0.500 (p = 0.004). Urinary catecholamines were not correlated with LV mass index. LV mass index correlated significantly with plasma renin activity (r = 0.346, p = 0.050), and aldosterone (r = 0.559, p = 0.001). There was a very significant correlation between LV mass index and parathyroid hormone (r = 0.719, p = 0.00001) even after adjustment for mean 24-hour systolic and diastolic BPs. These results clearly demonstrate that ambulatory BP determinants but not office BP parameters are well correlated with LV hypertrophy in essential hypertension. Nonhemodynamic factors are important determinants of LV mass as well. Besides the renin-angiotensin-aldosterone system, parathyroid hormone appears to play an important role in cardiac hypertrophy.     

Effect of endurance training on blood pressure at rest, during exercise and during 24 hours in sedentary men

The effect of 4 months of physical training on resting, exercise and 24-hour blood pressure (BP) was studied using a randomized crossover design in 26 healthy, sedentary men, with an average age of 39 +/- 10 (standard deviation) years. Peak oxygen uptake increased by 14% (p less than 0.001) and the physical working capacity at a heart rate of 130 beats/min by 25% (p less than 0.001). The heart rate was reduced by 7 beats/min at night (p less than 0.01) and by 6 beats/min during the day (p less than 0.001). Training-induced changes of BP varied according to measuring conditions. A decrease in BP at rest while sitting in the morning in the laboratory was significant for diastolic (-5 mm Hg, p less than 0.01) but not for systolic BP. During exercise, systolic BP was significantly lower after training, when measured at the same submaximal workloads. However, when workload was expressed as a percentage of peak oxygen uptake, systolic BP was not different before and after training. When measured during 24 hours, the training-induced change in BP was not significant at night either for systolic or diastolic BP. During the day the decrease in diastolic BP was significant (-5 mm Hg, p less than 0.001), but the change in systolic BP was not.     

Effects of celecoxib on ambulatory blood pressure in hypertensive patients on ACE inhibitors

Nonselective nonsteroidal anti-inflammatory agents have been shown to attenuate the antihypertensive efficacy of ACE inhibitors with average increases in systolic blood pressure (BP) of 5 to 10 mm Hg. Less is known about the specific cyclooxygenase-2 (COX-2) inhibitors now widely used for the treatment of arthritis. The objective of this study was to determine the effects of celecoxib compared with placebo on 24-hour BP levels in ACE inhibitor-treated patients with hypertension. This was a randomized, double-blind, placebo-controlled, parallel-group clinical trial involving 178 men and women (mean age, 53 years) with essential hypertension who were treated and controlled with lisinopril monotherapy (10 to 40 mg daily). Baseline BP values were obtained using 24-hour ambulatory recordings. Patients received either celecoxib, 200 mg twice daily (twice the recommended dose for osteoarthritis) (n=91), or placebo (n=87) for 4 weeks, and changes in the 24-hour BP, body weight, and clinical laboratory parameters were assessed. Mean changes from baseline in the 24-hour systolic and diastolic BP were 2.6/1.5+/-0.9/0.6 mm Hg on celecoxib versus 1.0/0.3+/-1/0.6 mm Hg on placebo (P=0.34 for systolic BP; P=0.45 for diastolic BP). The proportion of patients whose 24-hour BP increased by at least 5, 10, 15, or 20 mm Hg were also similar on celecoxib and placebo. No changes in body weight, serum creatinine, or potassium occurred in either group. Thus, these data demonstrate that high doses of celecoxib have no significant effect on the antihypertensive effect of the ACE inhibitor lisinopril. The placebo-subtracted changes observed in 24-hour BP (1.6/1.2 mm Hg) are less than what has been reported for nonselective nonsteroidal anti-inflammatory agents in ACE inhibitor-treated patients.     

Effectiveness of the once-daily calcium antagonist, lacidipine, in controlling 24-hour ambulatory blood pressure

The efficacy of the new once-daily dihydropyridine calcium antagonist, lacidipine, in reducing ambulatory intraarterial blood pressure (BP) was examined in 12 untreated hypertensive patients. The intraarterial recording was commenced 24 hours before the first 4-mg dose and was continued for a further 24 hours thereafter. After dose titration and chronic therapy, a second 24-hour ambulatory BP recording was made. There was a steady onset of drug action, maximal at 2 hours, but with reflex tachycardia after the first dose. Chronic administration reduced BP throughout the 24-hour period, without tachycardia. Mean daytime reduction in BP was 20 mm Hg systolic (p less than 0.005) and 12 mm Hg diastolic (p less than 0.02). Mean nighttime reduction was 8-mm Hg systolic (p less than 0.05) and 6-mm Hg diastolic (difference not significant). There was no postural decrease in BP on 60 degrees head-up tilting and hypotensive action was maintained during isometric exercise (reduction at peak of 32/18 mm Hg, p less than 0.05) and throughout dynamic exercise (reduction at peak of 23/14 mm Hg, p less than 0.05). Lacidipine is an effective once-daily antihypertensive agent, with good control of stress response.     

Therapy of patients with arterial hypertension with fixed dose combination of losartan and hydrochlorothiazide. Effect on 24 hour blood pressure and left-ventricular hypertrophy

Twenty four hour blood pressure (BP) monitoring was carried out and structural state of left ventricular myocardium assessed in 20 patients with mild and moderate hypertension before and after 24 weeks of therapy with Hyzaar - fixed dose combination of losartan (50 mg) and hydrochlorothiazide (12.5 mg). According to data of 24-hour BP monitoring the use of Hyzaar was associated with lowering of diurnal (by 26.9/17.2+/-3/2 mm Hg, p<0.001), nocturnal (by 32.6/18.9+/-3/2 mm Hg, p<0.001), pulse (p<0.001) BP, and rate of morning systolic BP rise (p<0.05), decrease of nocturnal systolic and diastolic BP variability, and improvement of 24-hour BP rhythm. Trough/peak coefficients for systolic and diastolic BP (70 and 76%, respectively) reflected sufficient and steady hypotensive effect throughout 24 hours after single dose of Hyzaar. Target BP level was achieved in 70% of patients. At the background of 24-week treatment with Hyzaar left ventricular myocardial mass index significantly decreased (from 120.1+/-3.5 to 108.6+/-3.1 g/m2, D=11.5+/-1.0, p<0.001) and became normal in 60% of patients. Correlation analysis revealed independence of cardioprotective action of therapy from its hypotensive activity. Thus therapy with Hyzaar produced hypotensive and cardioprotective effects which were independent from each other.     

Association of office and ambulatory blood pressure with blood lead in workers before occupational exposure

In view of decreasing lead exposure and guidelines endorsing ambulatory above office blood pressure (BP) measurement, we reassessed association of BP with blood lead (BL) in 236 newly employed men (mean age, 28.6 years) without previous lead exposure not treated for hypertension. Office BP was the mean of five auscultatory readings at one visit. Twenty-four-hour BP was recorded at 15- and 30-minute intervals during wakefulness and sleep. BL was determined by inductively coupled plasma mass spectrometry. Systolic/diastolic office BP averaged 120.0/80.7 mm Hg, and the 24-hour, awake, and asleep BP 125.5/73.6, 129.3/77.9, and 117.6/65.0 mm Hg, respectively. The geometric mean of blood lead was 4.5 μg/dL (interquartile range, 2.60–9.15 μg/dL). In multivariable-adjusted analyses, effect sizes associated with BL doubling were 0.79/0.87 mm Hg (P = .11/.043) for office BP and 0.29/?0.25, 0.60/?0.10, and ?0.40/?0.43 mm Hg for 24-hour, awake, and asleep BP (P ≥ .33). Neither office nor 24-hour ambulatory hypertension was related to BL (P ≥ .14). A clinically relevant white coat effect (WCE; office minus awake BP, ≥20/≥10 mm Hg) was attributable to exceeding the systolic or diastolic threshold in 1 and 45 workers, respectively. With BL doubling, the systolic/diastolic WCE increased by 0.20/0.97 mm Hg (P = .57/.046). Accounting for the presence of a diastolic WCE, reduced the association size of office diastolic BP with BL to 0.39 mm Hg (95% confidence interval, ?0.20 to 1.33; P = .15). In conclusion, a cross-sectional analysis of newly hired workers before lead exposure identified the WCE as confounder of the association between office BP and BL and did not reveal any association between ambulatory BP and BL.     

Relationship of dietary linoleic acid to blood pressure. The International Study of Macro-Micronutrients and Blood Pressure Study [corrected

Findings from observational and interventional studies on the relationship of dietary linoleic acid, the main dietary polyunsaturated fatty acid, with blood pressure have been inconsistent. The International Study of Macro-Micronutrients and Blood Pressure is an international cross-sectional epidemiological study of 4680 men and women ages 40 to 59 years from 17 population samples in China, Japan, United Kingdom, and United States. We report associations of linoleic acid intake of individuals with their blood pressure. Nutrient intake data were based on 4 in-depth multipass 24-hour dietary recalls per person and 2 timed 24-hour urine collections per person. Systolic and diastolic blood pressures were measured 8 times at 4 visits. With several models to control for possible confounders (dietary or other), linear regression analyses showed a nonsignificant inverse relationship of linoleic acid intake (percent kilocalories) to systolic and diastolic blood pressure for all of the participants. When analyzed for 2238 "nonintervened" individuals (not on a special diet, not consuming nutritional supplements, no diagnosed cardiovascular disease or diabetes, and not taking medication for high blood pressure, cardiovascular disease, or diabetes), the relationship was stronger. With adjustment for 14 variables, estimated systolic/diastolic blood pressure differences with 2-SD higher linoleic acid intake (3.77% kcal) were -1.42/-0.91 mm Hg (P<0.05 for both) for nonintervened participants. For total polyunsaturated fatty acid intake, blood pressure differences were -1.42/-0.98 mm Hg (P<0.05 for both) with 2 SD higher intake (4.04% kcal). Dietary linoleic acid intake may contribute to prevention and control of adverse blood pressure levels in general populations.     

Morning blood pressure peak,QT intervals,and sympathetic activity in hypertensive patients

We investigated the relation between morning blood pressure (BP) variations, sympathetic activity, and QT intervals in 156 never-treated subjects with essential hypertension and different patterns of morning BP increase. The morning BP peak (MP) was defined as a rise in systolic BP >or=50 mm Hg and/or diastolic BP >or=22 mm Hg during early morning (6:00 to 10:00 AM) compared with mean BP during the night. Clinical characteristics of patients with morning BP peak (MP+, n= 69, morning systolic BP=+54+/-4, diastolic BP=+32+/-5 mm Hg) did not differ from patients without BP peak (MP-, n= 87, morning systolic BP=+24+/-5, diastolic BP=+19+/-3 mm Hg). The daytime (10:00 AM to 10:00 PM) and the nighttime (10:00 PM to 6:00 AM) BP profile did not differ between the two groups. During daytime and nighttime ECG monitoring, the corrected QT (QTc) interval, and QTc dispersion did not differ significantly between the two groups, whereas during the morning period the QT values were significantly broader in the MP+ group compared with the MP- group (P相似文献   

Effect of body weight changes on 24-hour blood pressure and left ventricular mass in hypertension: a 4-year follow-up

BACKGROUND: Few data are available on the long-term effects of weight loss on 24-h blood pressure (BP) and left ventricular mass in overweight hypertensive patients. METHODS: A total of 181 never-treated overweight hypertensive subjects (body mass index, 25 to 39 kg/m(2), office BP 145/94 +/- 12/7 mm Hg) had 24-h BP monitoring and echocardiography twice, at baseline and after 3.8 +/- 2 years (minimum 1 year). None of the subjects received antihypertensive drugs during the follow-up. Main outcome measures were changes in 24-h BP and in left ventricular mass. RESULTS: Percent change in body weight had a direct relationship with 24-h BP changes (r = 0.35 and 0.31 for systolic and diastolic BP, respectively; both P <.001). The associations with office BP changes (r = 0.13, P =.10 for systolic BP; r = 0.15, P =.06 for diastolic BP) were significantly weaker (both P <.01, z test). The patients who lost weight during follow-up (n = 106) had a significantly lower increase in 24-h BP (+0.6 +/- 9/ +0.2 +/- 6 v +4.9 +/- 9/ +2.7 +/- 7 mm Hg for systolic/diastolic BP, both P <.01) and in left ventricular mass (-3 +/- 30 g v +9 +/- 32 g, P <.02) than the remaining subjects. In a multiple linear regression, a 10% weight loss independently predicted a 4.3/3.8 mm Hg decrease in 24-h systolic/diastolic BP. CONCLUSIONS: Long-term weight loss determines a sustained BP reduction during the 24 h and a decrease in left ventricular mass in overweight hypertensive subjects. The relation of weight loss with ambulatory BP changes is closer than that with office BP.     

High potassium intake blunts the effect of elevated sodium intake on blood pressure levels

The purpose of this study was to investigate the influence of dietary potassium on the sodium effect on blood pressure (BP) in the general population and the adherence of current recommendations for sodium and potassium intake. An overnight (12-hour) urine sample was collected in a population-based study to investigate cardiovascular risk. A sub-sample of 1285 subjects (age range, 25–64 years) free from any medication interfering with BP or potassium excretion was studied. Of the participants, 86.0% consumed over 6 g of salt/day and 87.7% less than the recommended intake of potassium (4.7 g). Potassium excretion and the sodium to potassium ratio were significantly related to systolic and diastolic BP only in subjects consuming more than 6 g/day of salt. Subjects in the highest sodium to potassium ratio quartile (surrogate of unhealthy diet) presented 8 mm Hg and 7 mm Hg higher values of systolic and diastolic BP, respectively, when compared with the first quartile, while individuals in the fourth quartile of urinary potassium excretion (healthier diet) showed 6 mm Hg and 4 mm Hg lower systolic and diastolic BP, respectively, compared with the first quartile. Our data indicate that when people have an increased intake of potassium, high intake of sodium is not associated with higher BP.     

What is the value of home blood pressure measurement in patients with mild hypertension?

To investigate the value of home blood pressure (BP) measurements, the BP was recorded daily by the patient at home and compared with recordings in the physician's office and with a 24-hour BP recording taken with a noninvasive ambulatory BP recorder in a group of 93 patients with mild untreated hypertension. Office BPs (mean 148/94 mm Hg) were higher than either home (138/89 mm Hg) or average 24-hour BPs (131/89 mm Hg). For systolic BP, home and office measurements gave similar correlations with 24-hour BP (0.67 and 0.55). For diastolic BP, however, home readings were lower and more accurate (0.76 vs 0.36). Thus, our findings indicate that home readings reflect the overall level of BP more reliably than office readings, and if due consideration is given to the fact that they are usually lower than office readings, they may be used as an alternative and cost-effective means of evaluating patients with mild hypertension.     

Dietary phosphorus and blood pressure: international study of macro- and micro-nutrients and blood pressure

Raised blood pressure is a leading cause of morbidity and mortality worldwide; improved nutritional approaches to population-wide prevention are required. Few data are available on dietary phosphorus and blood pressure and none are available on possible combined effects of phosphorus, magnesium, and calcium on blood pressure. The International Study of Macro- and Micro-Nutrients and Blood Pressure is a cross-sectional epidemiologic study of 4680 men and women ages 40 to 59 from 17 population samples in Japan, China, United Kingdom, and United States. Blood pressure was measured 8 times at 4 visits. Dietary intakes were obtained from four 24-hour recalls plus data on supplement use. Dietary phosphorus was inversely associated with blood pressure in a series of predefined multiple regression models, with the successive addition of potential confounders, both nondietary and dietary. Estimated blood pressure differences per 232 mg/1000 kcal (2 SD) of higher dietary phosphorus were -1.1 to -2.3 mm Hg systolic/-0.6 to -1.5 mm Hg diastolic (n=4680) and -1.6 to -3.5 mm Hg systolic/-0.8 to -1.8 mm Hg diastolic for 2238 "nonintervened" individuals, ie, those without special diet/nutritional supplements or diagnosis/treatment for cardiovascular disease or diabetes. Dietary calcium and magnesium, correlated with phosphorus (partial r=0.71 and r=0.68), were inversely associated with blood pressure. Blood pressures were lower by 1.9 to 4.2 mm Hg systolic/1.2 to 2.4 mm Hg diastolic for people with intakes above versus below country-specific medians for all 3 of the minerals. These results indicate the potential for increased phosphorus/mineral intake to lower blood pressure as part of the recommendations for healthier eating patterns for the prevention and control of prehypertension and hypertension.     

Assessment of blood pressure in patients with Type 2 diabetes: comparison between home blood pressure monitoring, clinic blood pressure measurement and 24-h ambulatory blood pressure monitoring.

AIMS: To compare a home blood pressure (BP) monitoring device and clinic BP measurement with 24-h ambulatory BP monitoring in patients with Type 2 diabetes mellitus (DM). METHODS: Fifty-five patients with type 2 DM had BP measured at three consecutive visits to the DM clinic by nurses using a stethoscope and mercury sphygmomanometer (CBP). Twenty-four-hour ambulatory BP was measured using a Spacelabs 90207 automatic cuff-oscillometric device (ABPM). Subjects were then instructed in how to use a Boots HEM 732B semiautomatic cuff-oscillometric home BP monitoring device and measured BP at home on three specified occasions on each of 4 consecutive days at varying times (HBPM). RESULTS: Correlations between HBPM and ABPM were r = 0.88, P < 0.001 for systolic BP and r = 0.76, P < 0.001 for diastolic BP, with correlations between CBP and ABPM being systolic r = 0.59, P < 0.001, diastolic r = 0.47, P < 0.001. HBPM agreed with ABPM more closely compared with CBP (CBP +10.9/+3.8 (95% confidence intervals (CI) 6.9, 14.8/1.6, 6.1) vs. HBPM +8.2/+3.7 (95% CI 6.0, 10.3/2.0, 5.4)). The sensitivity, specificity and positive predictive value of HBPM in detecting hypertension were 100%, 79% and 90%, respectively, compared with CBP (85%, 46% and 58%, respectively). CONCLUSIONS: In patients with Type 2 DM, home BP monitoring is superior to clinic BP measurement, when compared with 24-h ambulatory BP, and allows better detection of hypertension. It would be a rational addition to the annual review process. Diabet. Med. 18, 431-437 (2001)     

Effect of dietary patterns on ambulatory blood pressure : results from the Dietary Approaches to Stop Hypertension (DASH) Trial. DASH Collaborative Research Group.

We measured ambulatory blood pressure (ABP) in 354 participants in the Dietary Approaches to Stop Hypertension (DASH) Trial to determine the effect of dietary treatment on ABP (24-hour, day and night) and to assess participants' acceptance of and compliance with the ABP monitoring (ABPM) technique. After a 3-week run-in period on a control "typical" American diet, subjects (diastolic blood pressure [BP], 80 to 95 mm Hg; systolic BP, <160 mm Hg; mean age, 45 years) were randomly assigned to 1 of 3 diets for an 8-week intervention period: a continuation of the control diet; a diet rich in fruits and vegetables; and a "combination" diet that emphasized fruits, vegetables, and low-fat dairy products. We measured ABP at the end of the run-in and intervention periods. Both the fruit/vegetable and combination diets lowered 24-hour ABP significantly compared with the control diet (P<0. 0001 for systolic and diastolic pressures on both diets: control diet, -0.2/+0.1 mm Hg; fruit/vegetable diet, -3.2/-1.9 mm Hg; combination diet, -4.6/-2. 6 mm Hg). The combination diet lowered pressure during both day and night. Hypertensive subjects had a significantly greater response than normotensives to the combination diet (24-hour ABP, -10.1/-5.5 versus -2.3/-1.6 mm Hg, respectively). After correction for the control diet responses, the magnitude of BP lowering was not significantly different whether measured by ABPM or random-zero sphygmomanometry. Participant acceptance of ABPM was excellent: only 1 participant refused to wear the ABP monitor, and 7 subjects (2%) provided incomplete recordings. These results demonstrate that the DASH combination diet provides significant round-the-clock reduction in BP, especially in hypertensive participants.     

Blood pressure and renal blood flow responses to dietary calcium and sodium intake in humans.

This study was designed to determine the interaction between salt and calcium intake on blood pressure (BP) and renal blood flow (RBF) in a predominantly white population. We measured BP and RBF (P-aminohippurate [PAH] clearance) in hypertensive patients after 7 days on a low salt/low calcium diet and again after either a high salt/high calcium diet (HS/HC) or a high salt/low calcium (HS/LC) diet for another 7 days. Compared to low salt BP, both high salt diets increased BP, but the increase with high salt/low calcium was significantly greater than with high salt/high calcium (+14.6 +/- 3.9/+8.2 +/- 1.7 mm Hg v +7.5 +/- 1.9/+2.5 +/- 1.4 mm Hg; systolic/diastolic, both P less than or equal to .05). PAH clearance increased 26 +/- 13 mL/min/1.73 m2 on the HS/HC diet but only 10 +/- 17 mL/min/1.73 m2 on HS/LC (P = .05 between groups). These data suggest that a low calcium diet may contribute to the phenomenon of salt sensitivity in a white population. The low calcium intake appears to affect both the systemic and renal vasculature.     

Multiple clinic and home blood pressure measurements versus ambulatory blood pressure monitoring.

To compare multiple clinic and home blood pressure (BP) measurements and ambulatory BP monitoring in the clinical evaluation of hypertension, we studied 239 middle-aged pharmacologically untreated hypertensive men and women who were referred to the study from the primary healthcare provider. Ambulatory BP monitoring was successfully completed for 233 patients. Clinic BP was measured by a trained nurse with a mercury sphygmomanometer and averaged over 4 duplicate measures. Self-recorded home BP was measured with a semiautomatic oscillometric device twice every morning and twice every evening on 7 consecutive days. Ambulatory BP was recorded with an auscultatory device. Two-dimensionally controlled M-mode echocardiography was successfully performed on 232 patients. Twenty-four-hour urinary albumin was determined by nephelometry. Clinic BP was 144.5+/-12.6/94.5+/-7.4 mm Hg, home BP (the mean of 14 self-recorded measures) was 138.9+/-13.1/92.9+/-8.6 mm Hg, home morning BP (the mean of the first 4 duplicate morning measures) was 137.1+/-13.7/92.4+/-9.2 mm Hg, daytime ambulatory BP was 148.3+/-13. 9/91.9+/-7.8 mm Hg, nighttime ambulatory BP was 125.5+/-16.4/75. 6+/-8.9 mm Hg, and 24-hour ambulatory BP was 141.7+/-14.0/87.2+/-7.6 mm Hg. Pearson correlation coefficients of clinic, home, home morning, and daytime ambulatory BPs to albuminuria and to the characteristics of the left ventricle were nearly equal. In multivariate regression analyses, 36% (P<0.0001) of the cross-sectional variation in left ventricular mass index was attributed to gender and home morning systolic BP in models that originally included age, gender, and clinic, self-measured home morning, and ambulatory daytime, nighttime, and 24-hour systolic and diastolic BPs. We concluded that carefully controlled nonphysician-measured clinic and self-measured home BPs, when averaged over 4 duplicate measurements, are as reliable as ambulatory BP monitoring in the clinical evaluation of untreated hypertension.     

The circadian blood pressure pattern in ambulatory normal subjects

Ambulatory blood pressure (BP) monitoring using a portable noninvasive device capable of automatically measuring and recording BP every 7.5 minutes during a 24-hour study period was performed in 34 normal volunteers on 2 separate occasions, 2 to 8 weeks apart, to test the consistency of the whole-day blood pressure pattern. The average of all systolic BPs measured during the second study day was within 10 mm Hg of that measured during the first study day in 79% of the subjects, and the respective diastolic BP averages were within 5 mm Hg of each other in 65 % of the subjects; 53 % satisfied both of these criteria. The reproducibility of the circadian pattern of the BP was tested by dividing the 24-hour day into 12 consecutive 2-hour BP averages. When the corresponding 2-hour periods on the 2 study days were matched, there were strong correlations (r > 0.70) within most subjects for both the systolic and diastolic BP averages of the 2-hour periods (76% and 68% of subjects) and for the relative rank values of the periods (62% and 56%). Moreover, there were no significant differences between the averages (for all subjects together) on the 2 study days of the highest and lowest systolic and diastolic 2-hour BP values; similarly, the times at which these extreme values occurred on the 2 study days corresponded closely. Thus, in normal subjects there is a strong tendency for the circadian pattern and the actual levels of BP to be consistent between 24-hour study periods.