Single Blood Pressure Measurement Research Articles

Hypertension in people with Type 2 diabetes: knowledge-based diabetes-specific guidelines.

The International Diabetes Federation (Europe) has updated these guidelines on hypertension management specifically in Type 2 diabetes in the light of recent results of the first prospective, randomized controlled studies to investigate clinical outcomes in people with diabetes and hypertension. The guidelines are knowledge based, i.e. based not only on evidence originating from clinical trials, but also from epidemiological and pathophysiological studies. A successful management strategy requires the following components: 1. Regular surveillance to detect developing hypertension and other cardiovascular (CV) risk factors. 2. Considering more frequent monitoring and review of CV risk factors if any single blood pressure (BP) measurement > 140/85 mmHg (or 130/75 if microalbuminuria); when appropriate, using ambulatory or home monitoring to establish the baseline BP. 3. Considering other CV risk factors, such as a raised albumin excretion rate, in setting the intervention threshold. 4. Individualizing the target BP in accordance with other CV risk factors. 5. Agreeing lifestyle and therapeutic interventions with the patient, with education and empowerment as required. 6. Implementing lifestyle modifications, including controlling calorie, salt and alcohol intake, increased physical activity, weight control and smoking cessation. 7. Therapeutic strategy: the primary goal of therapy is to reduce BP markedly. Combination therapy is often necessary, e.g. an angiotensin converting enzyme (ACE) inhibitor and a diuretic. Some classes are particularly useful for certain patients, notably longer-acting ACE inhibitors, angiotensin 2 receptor antagonists (A2RAs) and calcium antagonists in those at risk of diabetic nephropathy, loop diuretics and thiazides in those at risk of hyperkalaemia, beta-blockers and calcium antagonists (except short-acting dihydropyridines) in patients with angina, beta-blockers and ACE inhibitors after a myocardial infarction or in those with left ventricular dysfunction, and thiazide diuretics and long-acting dihydropyridine calcium antagonists for isolated systolic hypertension. A2RAs should be particularly considered when ACE inhibitors are not tolerated. alpha 1-Blockers should not be considered first line in the absence of outcome data. Cost of drugs will modify these strategies in developing countries. 8. Monitoring response to therapies and, if target levels are not achieved, either intensifying drug therapy if the CV risk justifies it, or reassessing the target. 9. Maintaining a quality assurance strategy. This strategy is summarized in a simple, practical management algorithm.

Daily blood pressure variations in patients with type 1 diabetes mellitus and nephropathy

То study a relationship between systemic hemodynamic parameters, albuminuria, and autonomic dysfunction in patients with type 1 diabetes mellitus (DM-1) without obvious nephropathy, the authors examined 55 patients in the inpatient setting. Twenty-nine patients had a normal urinary albumin excretion (CAE), 26 patients had microalbuminuria. 24-hour blood pressure monitoring (24-h BPM) was occillometrically made. The average daily, average diurnal and nocturnal values of systolic and diastolic blood pressure (BP) were significantly higher in DM-1 patients with microalbuniuria than in those with normal UAE. Routine autonomic cardiovascular tests showed that the incidence and severity of autonomic neuropathy were also higher in patients with microalbuminuria. Arterial hypertension (AH) diagnosed in compliance with the 24-h BPM criteria was detected. in 17.2%) of the DM-1 patients with normal UAE and in 42.3%) of the patients with microalbuminuria. According to the data of 24-h BPM, the incidence of arterial hypertension was 1.7 times as high as that evidenced by single BP measurements. The specific feature of circadian hemodynamic variations in patients with DM-1 was a low nocturnal BP decrease. 37.9%) of the patients with normoalbuminuria and 61.5%) of the patients with microalbuminuria had no normal (>10%)) nocturnal BP lowering. Stepwise regression analysis has ascertained that in patients with DM-1 without obvious nephropathy, systemic hemodynamic disorders are associated with albuminuria, autonomic dysfunction, and glycemic monitoring quality.

Relevance of blood pressure variation in the circadian onset of cardiovascular events.

Ambulatory blood pressure monitoring (ABPM) is a highly useful diagnostic tool as it can detect non-dipping and can distinguish masked hypertension, white-coat hypertension and sustained hypertension. Furthermore, measurement of blood pressure using ABPM has greater prognostic strength than single clinic blood pressure measurements. The Systolic Hypertension in Europe study, for example, found that elevation of ambulatory systolic blood pressure, but not conventional single cuff systolic blood pressure, by 10 mmHg was associated with adverse cardiovascular outcomes. Blood pressure follows a circadian rhythm, with peak levels during the morning hours. The morning period has also been associated with a greater risk for cardiovascular events compared with the rest of the 24 h. The morning surge in blood pressure, along with haemostatic changes that promote thrombosis, is believed to contribute to this heightened risk. Long-acting antihypertensive agents that provide blood pressure control throughout the 24-h dosing interval, including the morning hours, are the most appropriate therapeutic approach to hypertension. Direct comparative studies with telmisartan and other angiotensin-II receptor blockers and with amlodipine have shown that telmisartan has a long duration of action and controls blood pressure over the 24-h dosing period.

Age-specific relevance of usual blood pressure to vascular mortality: a meta-analysis of individual data for one million adults in 61 prospective studies

The age-specific relevance of blood pressure to cause-specific mortality is best assessed by collaborative meta-analysis of individual participant data from the separate prospective studies. Information was obtained on each of one million adults with no previous vascular disease recorded at baseline in 61 prospective observational studies of blood pressure and mortality. During 12.7 million person-years at risk, there were about 56000 vascular deaths (12000 stroke, 34000 ischaemic heart disease [IHD], 10000 other vascular) and 66000 other deaths at ages 40-89 years. Meta-analyses, involving "time-dependent" correction for regression dilution, related mortality during each decade of age at death to the estimated usual blood pressure at the start of that decade. Within each decade of age at death, the proportional difference in the risk of vascular death associated with a given absolute difference in usual blood pressure is about the same down to at least 115 mm Hg usual systolic blood pressure (SBP) and 75 mm Hg usual diastolic blood pressure (DBP), below which there is little evidence. At ages 40-69 years, each difference of 20 mm Hg usual SBP (or, approximately equivalently, 10 mm Hg usual DBP) is associated with more than a twofold difference in the stroke death rate, and with twofold differences in the death rates from IHD and from other vascular causes. All of these proportional differences in vascular mortality are about half as extreme at ages 80-89 years as at ages 40-49 years, but the annual absolute differences in risk are greater in old age. The age-specific associations are similar for men and women, and for cerebral haemorrhage and cerebral ischaemia. For predicting vascular mortality from a single blood pressure measurement, the average of SBP and DBP is slightly more informative than either alone, and pulse pressure is much less informative. Throughout middle and old age, usual blood pressure is strongly and directly related to vascular (and overall) mortality, without any evidence of a threshold down to at least 115/75 mm Hg.

Analysis of Recent Papers in Hypertension

Analysis of Recent Papers in Hypertension

Antenatal screening in rural Bangladesh: its role in maternal outcomes

The inability of antenatal markers to predict adverse maternal outcomes has led some people to reject antenatal care in resource poor settings altogether as a strategy to fight maternal and perinatal mortality. This population-based cohort study assessed whether antenatal screening can identify women at risk for severe labor and delivery complications in rural Bangladesh. The results suggest that trained midwives in antenatal services cannot distinguish women who need special labor and delivery care from those who do not because most women have no advance warning signs. A single blood pressure measurement and the assessment of fundal height however may detect a substantial number of women with hypertensive diseases and twin pregnancies. Further women who had an antenatal visit in this study were four times more likely to deliver with a midwife than women who had no antenatal visit. Although antenatal care is not able to identify those who will develop complications if provided in concurrence with effective emergency obstetric care (EOC) and delivered in skilled hands it may become an effective instrument to give women information encourage attendance by a trained midwife diagnose hypertensive diseases and keep watch on the woman prepare for the risks of twin pregnancies and facilitate better use of EOC services. (full text)

Benefits of twenty-four-hour blood pressure control.

Despite the clear recognition that blood pressure does not remain at the same level over a 24-h period, normally falling during sleep and rising during times of physical or mental activity, a single blood pressure measurement gained during the working day is conventionally used to classify a patient as normotensive or hypertensive. ANTIHYPERTENSIVE TREATMENT AND 24-H BLOOD PRESSURE CONTROL: There is still no definitive proof that antihypertensive drugs providing full 24-h blood pressure control will lead to improved outcomes compared with drugs that provide incomplete 24-h blood pressure control. However, there is a large body of evidence showing that cardiovascular target-organ damage is correlated with 24-h blood pressure measurements and supportive evidence that a fall in these 24-h measurements can predict a likely reduction in cardiovascular target-organ damage. In deciding which antihypertensive agent to use, physicians should select, where possible, those agents that provide blood pressure control through the 24-h period.

Is There Tension in Hypertension?

To the Editor. —The interesting study by Dr Markovitz and colleagues 1 about psychological predictors of hypertension and the accompanying Editorial 2 shed extra light on the pathophysiological role and prognostic importance of psychological factors in organic diseases. 3,4 However, one must question the criteria for hypertension used by the authors: (1) systolic blood pressure of 160 mm Hg or higher, diastolic blood pressure of 95 mm Hg or higher, or both; and (2) the use of antihypertensive medications. 1 I get the impression that a single blood pressure measurement satisfied the investigators. The recent report of the Joint National Committee on Detection, Evaluation, and Treatment on High Blood Pressure states that hypertension should not be diagnosed on the basis of a single measurement and requires at least three elevated readings during 1 to several weeks (unless systolic blood pressure is 210 mm Hg or higher and/or diastolic blood pressure

Blood Pressure and Serum Creatinine

To the Editor. —The article by Perneger et al 1 on the effect of increased blood pressure on kidney function supports the conclusion that we reached in a previous study. In our study, 2 time averaged blood (clinic blood pressures recorded quarterly for a mean period of approximately 10 years) in a hypertensive group and a normotensive control group predicted change in serum creatinine levels. Several methodological issues are relevant to both studies. First, since hypertension may occur as a consequence of renal damage, it might be more useful to look at blood pressure levels measured prior to a change in renal function (as in the study by Perneger et al) instead of blood pressure levels measured during the follow-up period, as we used. Nevertheless, because of the unreliability of single blood pressure measurements, it may be necessary to obtain several baseline blood pressure values to see their effect

Aging, hypertension, and renal damage: generalities and results of the Cardiovascular Study in the Elderly.

I N WESTERN SOCIETIES arterial hypertension is a common finding in people over the age of 65. In fact the elderly hypertensive population is made up not only of hypertensive persons who have aged, but also of those who have developed hypertension (mainly systolic) as a consequence of the vascular changes that are characteristic of old age. Ever since the epidemiologic studies conducted in the 60s and the 70s it is known that in the elderly the prevalence of hypertension is very high: 60% for systodiastolic hypertension and 15% to 45% for isolated systolic hypertension. However this particularly high figure may be due to the fact that most studies were based on a single blood pressure (BP) measurement. This may lead to an overestimation of the prevalence of hypertension, as we ourselves have been able to discover with repeated BP measurements over a period of 3 to 5 months of observation.1,2 Other trials have demonstrated a slightly lower prevalence,3,4 but confirm the importance of the phenomenon of hypertension in the elderly, particularly considering that in western countries the number of persons over the age of 65 increases by 4% each year; it has been calculated that by the year 2020 in Italy there will be some 11 million. It is well established that hypertension represents a major risk factor for cardiovascular diseases. This applies particularly to the elderly population where age itself represents a key factor in predicting the risk of atherosclerosis and its complications. Besides, the almost constant association with a deranged cerebral circulation and impaired cardiac and renal function exponentially increases the risk itself.

Accuracy of four indirect methods of blood pressure measurement, with hemodynamic correlations

In 38 adults undergoing cardiac surgery, 4 indirect blood pressure techniques were compared with brachial arterial blood pressure at predetermined intervals before and after cardiopulmonary bypass. Indirect blood pressure measurement techniques included automated oscillometry, manual auscultation, visual onset of oscillation (flicker) and return-to-flow methods. Hemodynamic measurements or calculations included heart rate, cardiac index, stroke volume index, and systemic vascular resistance index. Indirect and intraarterial blood pressure values were compared by simple linear regression by patient and measurement period. Measurement errors (arterial minus indirect blood pressure) were calculated, and stepwise regression assessed the relationship between measurement error and heart rate, cardiac index, stroke volume index, and systemic vascular resistance index. Indirect to intraarterial blood pressure correlation coefficients varied over time, with the strongest correlations often occurring at the first and last measurement periods (preinduction and 60 minutes after cardiopulmonary bypass), particularly for systolic blood pressure. Within-patient correlations between indirect and arterial blood pressure varied widely--they were consistently high or low in some patients. In other patients, correlations were especially weak with a particular indirect blood pressure method for systolic, mean, or diastolic blood pressure; in some cases indirect blood pressure was inadequate for clinical diagnosis of acute blood pressure changes or trends. The mean correlations between indirect and direct blood pressure values were, for systolic blood pressure: 0.69 for oscillometry, 0.77 for auscultation, 0.73 for flicker, and 0.74 for return-to-flow; for mean blood pressure: 0.70 for oscillometry and 0.73 for auscultation; and for diastolic blood pressure: 0.73 for oscillometry and 0.69 for auscultation. The mean measurement errors (arterial minus indirect values) for the individual indirect blood pressure methods were, for systolic: 0 mm Hg for oscillometry, 9 mm Hg for auscultation, -5 mm Hg for flicker, 7 mm Hg for return-to-flow; for mean: -6 mm Hg for oscillometry, and -3 mm Hg for auscultation; and for diastolic: -9 mm Hg for oscillometry and -8 mm Hg for auscultation. Mean measurement error for systolic blood pressure was thus least with automated oscillometry and greatest with manual auscultation, while standard deviations ranging from 9 to 15 mm Hg confirmed the highly variable nature of single indirect blood pressure measurements. Except for oscillometric diastolic blood pressure, a combination of systemic hemodynamics (heart rate, stroke volume index, systemic vascular resistance index, and cardiac index) correlated with each indirect blood pressure measurement error, which suggests that particular numeric ranges of these variables minimize measurement error.(ABSTRACT TRUNCATED AT 400 WORDS)

Blood pressure distribution in a school-age population aged 8-10 years: the Odense Schoolchild Study

This paper describes the distribution of systolic and diastolic blood pressures in a homogeneous population of 1330 schoolchildren (81% of the eligible population) aged 8-10 years in Odense, Denmark. A single blood pressure measurement was made. No significant difference in mean blood pressure between the sexes could be demonstrated. A significant age-related increase in systolic blood pressure of 4.4 mmHg/year and in diastolic blood pressure of 3.4 mmHg/year was observed. Weight and the heart rate were important determinants of blood pressure level. Other positive determinants were age and triceps skinfold thickness. There was a significant association between diastolic blood pressure and sexual maturation, which seemed to depend on body weight.

Effect of Timing and Number of Baseline Blood Pressure Determinations on Postural Blood Pressure Response

We hypothesized that the blood pressure response to standing may depend on the method of establishing baseline blood pressure. Three hundred elderly subjects previously completed a postural blood pressure protocol with three supine baseline blood pressure readings obtained two minutes apart prior to standing. Comparison of the readings showed a significant drop between the first and the second (P less than .001) but not between the second and third supine systolic blood pressures. The difference between the first supine systolic blood pressure and the one minute standing blood pressure was significantly greater than that between the third supine systolic blood pressure and the one minute standing blood pressure (P less than .001). A second group was prospectively studied to determine whether the change in blood pressure after standing was greater if only a single baseline reading was taken rather than multiple readings, and whether the decline in blood pressure over three readings was related to duration supine or to the number of blood pressures taken. This group also demonstrated a decline in systolic blood pressure with three serial readings. We conclude that supine blood pressure declines significantly between the first and second readings taken two minutes apart and is secondary to the repetition of readings and not the duration supine. However, this change in supine blood pressure does not significantly alter the blood pressure response to standing. Thus, it appears that a single baseline supine blood pressure measurement is adequate for determining the postural blood pressure response, and that pooling of multiple baseline readings may not be appropriate.

Bayesian Analysis of Diastolic Blood Pressure Measurement

A mathematical model is presented for measurements that include substantial fluctuation and error. Under the assumptions that the fluctuation-error variance is the same for all subjects, and that the distributions of fluctuation-error variance within subjects and "true" values of the measurements in the population are normal, Bayes' theorem produces a simple estimate of the "true" value of a measurement, and a standard error, conditional on a single observation. The model is easily extended to several observations. Methods for estimating the parameters of the model from a data set are presented, and applied to diastolic blood pressures of patients in the authors' primary care clinic. The test-retest reliability of a single blood pressure measurement for this population is 0.41. Because continuous measurements are often dichotomized into "normal" and "abnormal" ranges by a threshold criterion, the authors present formulas for the positive predictive value when a decision rule based on a given number of observations is used in a population with respect to a threshold criterion for the "true" values. For example, classifying their patients as hypertensive on the basis of the average of two readings exceeding 90 mm Hg diastolic pressure would have a positive predictive value of 52% for the "gold standard" of average diastolic pressure exceeding 90 mm Hg. Formulas to calculate the frequency with which patients will be classified "abnormal" by one decision rule but will be classified "normal" by later application of another rule are provided and used to "predict" the frequency with which this crossover phenomenon should have occurred in the enrollment phase of the Hypertension Detection and Follow-up Programs.(ABSTRACT TRUNCATED AT 250 WORDS)

Tracking and Prediction of Blood Pressure in Children

A significant but weak correlation between an initial and a subsequent blood pressure measurement in the same patient has been found in several previous longitudinal studies of blood pressure in children. In the current study, single determinations of blood pressure, weight, and height were recorded in 142 children at 5.9 to 9.5 years of age and again 9 years later. Both examinations were performed in a schoolroom. Body size at the first examination was associated with body size 9 years later. A significant correlation was noted between initial and subsequent raw systolic blood pressures (r = 0.36 in boys and in girls; P less than 0.01). Correlations of systolic blood pressure based on percentiles for age and for height and weight were smaller but also statistically significant. Correlations involving diastolic blood pressure, with use of raw blood pressure measurements, were significant only for boys (r = 0.24, P less than 0.05). Correlations were not improved when indices of body size were used. Single blood pressure measurements obtained under the usual conditions in a schoolroom had only slightly weaker correlations with subsequent blood pressure determinations than those obtained in studies in which considerable care was taken to achieve more "basal" measurements. This degree of blood pressure correlation is insufficient to allow accurate prediction of subsequent blood pressure levels on the basis of a single casual blood pressure measurement in an individual child. This result was indicated by a wide 95% confidence interval for the predicted subsequent systolic blood pressure, even when sex, initial diastolic blood pressure, weight, and change in weight were considered.

Relationship between longitudinal changes in blood pressure and stroke incidence.

The relationship of changes in blood pressure with time to stroke incidence was examined on members of the Adult Health Study sample who have participated in biennial clinical examinations at the Radiation Effects Research Foundation since their inception in 1958. The regression coefficient of blood pressure regressed on time (the increase in blood pressure per cycle) was used as an index of the change in blood pressure with time. Cox's regression analysis, a technique which is suitable for follow-up studies was used. The data suggest that a single blood pressure measurement is not sufficient for predicting risk; the accumulated value or average over a period of time should be considered for this purpose. In addition to the actual blood pressure, the increase in blood pressure with time is a risk factor, particularly for cerebral hemorrhage. Cerebral hemorrhage was more strongly related to diastolic than to systolic blood pressure, while cerebral infarction appeared to be more strongly related to systolic than to diastolic blood pressure.

The variability of blood pressure: Basal and casual measurements in adult twins

Basal and casual blood pressure measurements have been obtained under standardized conditions of study in 53 adult pairs of twins who were determined to be in good general health on the basis of health histories and medical examinations. These data have afforded an analysis of: differences between the left and right arms, and differences between casual and basal blood pressure measurements in individuals, and within and between pairs of twins. In both the casual and basal studies it can be seen from the critical MZ:DZ ratios that variability in the measured levels of the blood pressure (in these adult subjects in good general health) is predominantly under environmental influences. However, different comparisons of the monozygotic twin intrapair casual and basal variances indicate that there may be genetic as well as sex influences which are not effectively defined by single blood pressure measurements, at least in the normal range of this variable. It was found that: (1) Although the average of the blood pressures is unaffected by the arm employed, differences between pressures on the left arm and those on the right arm are an important consideration when comparing measurements taken on the same individual, or between the two members of a pair of twins. (This would also be an important consideration in the study of siblings and families.) (2) The conditions of study have a greater effect upon the interpretation of blood pressure data than might be implied by the relatively small differences in the average of the blood pressures taken under varying conditions of study. (3) Measurement of genetic, environmental, and sex influences upon blood pressure, as well as the association of blood pressure with such variables as weight and ponderal index, depend upon the conditions of study. (4) There are genetic and sex-influenced factors related to cardiac function which are not effectively described by single measurements of the level of the blood pressure. The analyses of these data on twins pose the question whether measured levels of the blood pressure constitute the most critical manifestation of the genetic and sexinfluenced variables to be investigated. The lability of the blood pressure, its reactivity to specific stimuli, the relationship of systolic to diastolic pressure, and, possibly, the correlation of blood pressure with other attributes may be the most promising avenues for further genetic investigations of this clinically important measurement.