Are some hypertensive patients overtreated? A prospective study of ambulatory blood pressure recording

Comparing office-based and ambulatory blood pressure monitoring in clinical trials

Ambulatory blood pressure monitoring (ABPM) is commonly used in clinical trials. Yet, its ability to detect blood pressure (BP) change in comparison to multiple office-based measurements has received limited attention. We recorded ambulatory and five daily pairs of random zero (RZ) BPs pre- and post-intervention on 321 adult participants in the multicentre Dietary Approaches to Stop Hypertension trial. Treatment effect estimates measured by ambulatory monitoring were similar to those measured by RZ and did not differ significantly for waking vs 24-h ambulatory measurements. For systolic BP, the standard deviations of change in mean 24-h ambulatory BP (8.0 mmHg among hypertensives and 6.0 mmHg among nonhypertensives) were comparable to or lower than the corresponding standard deviations of change in RZ-BP based on five daily readings (8.9 and 5.9 mmHg). The standard deviations of change for mean waking ambulatory BP (8.7 and 6.7 mmHg) were comparable to those obtained using three to four daily RZ readings. Results for diastolic BP were qualitatively similar. Ambulatory monitoring was more efficient (ie, a smaller sample size could detect a given BP change) than three to four sets of daily RZ readings and required fewer clinic visits. The average of 33 ambulatory BP readings during the waking hours had an efficiency comparable to that from the mean of four daily pairs of RZ-BPs. Participants readily accepted the ABPM devices, and their use requires less staff training. ABPM provides a useful alternative to RZ-BP measurements in clinical trials.

Effect of recorded home blood pressure measurements on the staging of hypertensive patients

OBJECTIVE

To compare clinic and home blood pressures for use in classifying patients in relation to a recent guideline for the diagnosis of hypertension.

METHODS

Fifty patients were studied and classified on the basis of clinic pressures, using the Joint National Committee VI criteria, into the categories of normal, high-normal and stage 1, 2 or 3 hypertension. The patients were given instructions for using the Omron IC home-recording device to take their blood pressure daily for 1 week and then return the units for data recall and entry. Average home-recorded pressures were calculated and patients reclassified in terms of the Joint National Committee VI criteria if their home pressures were higher or lower than their clinic pressures.

RESULTS

According to the clinic results, 18% of the participants had normal blood pressure, 16% had high-normal pressure, 48% were hypertensive stage 1, 16% were hypertensive stage 2 and 2% were hypertensive stage 3. Reclassification by recorded home pressures occurred in 54% of the participants: 40% downwards and 14% upwards. Only 46% remained in the same category for both clinic and recorded home pressures.

CONCLUSION

Recorded home blood pressure measurement provides an accurate, reliable and unbiased assessment. Using the Joint National Committee VI classification system for both clinic and recorded home blood pressures, the data on the home pressures led, in this sample, to a downward classification three times more frequently than an upward one. We therefore conclude that recording home blood pressure is a highly useful method for assigning the appropriate blood pressure classification when using the Joint National Committee VI guidelines.

Resistant hypertension and the birmingham hypertension square

Recent guidelines for the treatment of hypertension place great emphasis on tighter blood pressure control, especially in the presence of hypertensive target organ damage and diabetes. In order to achieve these treatment targets, more patients will require a combination of antihypertensive medications. However, resistant hypertension may have many possible underlying causes, and clinicians should appreciate how to detect and tackle these potential problems. Effective and synergistic combinations are therefore of vital importance, especially in patients with resistant hypertension. The choice of rational first- and second-line drugs that act in synergy could lead to better blood pressure management as well as significant financial savings for health care resources. The use of the Birmingham Hypertension Square for the optimum choice of add-in drugs for the treatment of resistant hypertension may aid management.

Ambulatory blood pressure monitoring and clinical characteristics of the true and white-coat resistant hypertension

The resistant hypertension has been differentiated in true resistant hypertension and white-coat resistant hypertension by using ambulatory blood pressure monitoring. White-coat resistant hypertension was defined as high clinic blood pressure, despite triple treatment for at least 3 months, but day-time blood pressure values < 135/85 mmHg. The aim of this study was to evaluate the presence of different clinical characteristics between two types of resistant hypertension. The study group consisted of 49 patients with essential hypertension, resistant to an adequate and appropriate triple-drug therapy, that included a diuretic, with all 3 drugs prescribed in near maximal doses and that had persistently elevated clinic blood pressure (> 140/90 mm Hg), for at least 3 months. They represented the 2% of 2500 hypertensive outpatients that referred at our Hypertension Unit. Patients with white-coat resistant hypertension (n=19) were older (p<0.05) than those with true resistant hypertension (n=30). The sodium intake (p<0.05) and alcohol intake (p<0.05) were significantly higher in patients with true resistant hypertension than in those with white-coat resistant hypertension. The renin plasma activity and plasma aldosterone were higher (p<0.05) in patients with true resistant hypertension than in those with white-coat resistant hypertension with normal plasma electrolyte balance. There were no significant differences in mean values of office systolic and diastolic blood pressures between white coat resistant hypertensives and true resistant hypertensives (165+17 vs 172+28 and 98+12 vs 102+14 mmHg). Day-time and night-time ambulatory 24-h-systolic and diastolic blood pressures were significantly higher in the true resistant hypertensive patients when compared with white-coat resistant hypertensives (153+15 vs 124+10 mmHg and 97+9 vs 76+6 mmHg all p<0.001). Day-time and night-time ambulatory 24-h-heart rate were significantly higher in the true resistant hypertensive patients when compared with white-coat resistant hypertensives (79+11 vs 71+9 beats/min; p<0.01; 68+9 vs 60+6 beats/min, p<0.001). The ABP readings were analysed by a Fourier series with 4 harmonics. According to the runs test both two groups of patients showed a circadian rhythm for both systolic and diastolic blood pressure. The nocturnal fall in SBP, DBP and HR was not different in both groups of patients. In conclusion, our findings showed that true resistant hypertensive patients were characterized both by higher heart rate and higher plasma renin activity values as an expression of a possible increased sympathetic activity. Thus, the combination of ABPM with the assessment of the clinical characteristics allow to differentiate better the true drug-resistant hypertension from the white coat resistant hypertension.

Importance of various methods of blood pressure measurement in clinical trials

Ambulatory blood pressure (ABP) monitoring and self-measurement of blood pressure (BP) are more reproducible than clinic BP measurement, minimize the white coat effect, and can reduce the sample size necessary to demonstrate the efficacy of a drug in clinical trials. For many years, the trough:peak ratio has been considered the key index for demonstrating the efficacy of antihypertensive agents. However, several potential problems are associated with the use of this index, and ABP monitoring makes it possible to examine changes in BP over the entire 24-hour period, not only at a preset time of peak effect and at the end of the dosing interval. The smoothness index provides more comprehensive information on the 24-hour BP control with treatment and avoids part of the problems encountered with the trough:peak ratio. One simple way to summarize the results of ABP monitoring in clinical trials is to provide the mean 24-hour BP difference from placebo and the BP decrease at trough. The numerous advantages summarized above make ABP monitoring an accepted method of BP measurement in hypertension therapy trials. Self-measurement of BP may be a valid and less expensive alternative to ABP monitoring.

Ambulatory blood pressure predicts end-organ damage only in subjects with reproducible recordings. HARVEST Study Investigators. Hypertension and Ambulatory Recording Venetia Study

OBJECTIVE

To determine whether the prediction of target-organ damage varies according to the reproducibility of 24 h blood pressure.

SETTING

Seventeen hypertension clinics in northeast Italy.

MAIN OUTCOME MEASURES

Correlations of left ventricular mass index and albumin excretion rate with 24 h and office blood pressures in relation to tertiles of ambulatory blood pressure reproducibility.

PATIENTS AND METHODS

In 716 consecutive, stage I, hypertensives enrolled in the Hypertension and Ambulatory Recording Venetia Study (HARVEST), ambulatory blood pressure monitoring was performed twice, 3 months apart In all subjects, the albumin excretion rate was measured by radioimmunoassay, and in 567, the left ventricular mass index was assessed by echocardiography.

RESULTS

The subjects were divided into tertiles of ambulatory blood pressure consistency (between-monitoring differences, regardless of the sign). In the tertile of subjects with good reproducibility, correlation coefficients of systolic and diastolic ambulatory blood pressure with left ventricular mass and urinary albumin excretion were significant and higher than those of office blood pressure. In contrast, in the two tertiles with poorer reproducibility, the coefficients were barely or not significant for both pressures. The advantage of ambulatory blood pressure over office blood pressure in predicting target-organ damage was no longer present for systolic blood pressure differences greater than 3.8 mmHg and diastolic blood pressure differences greater than 3.1 mmHg.

CONCLUSIONS

These data indicate that ambulatory blood pressure is a better predictor of left ventricular mass and urinary albumin excretion than office blood pressure, but only in subjects with good pressure reproducibility. Therefore, the assessment of hypertensive patients should be based on duplicate blood pressure monitorings. Recordings with 24 h systolic and diastolic blood pressure differences greater than 4 and 3 mmHg, respectively, should be considered with caution.

Limitations of the difference between clinic and daytime blood pressure as a surrogate measure of the 'white-coat' effect. Syst-Eur investigators

BACKGROUND

The difference between clinic and ambulatory average daytime blood pressures is frequently taken as a surrogate measure of the 'white-coat effect' (i.e. the pressor reaction triggered in the patient by the physician's visit).

OBJECTIVE

To assess the reproducibility of this difference and its relationship with clinic and average ambulatory daytime blood pressure levels.

DESIGN AND METHODS

These issues were addressed with two large groups of subjects in whom both clinic and ambulatory blood pressures were measured, namely 783 outpatients with systolic and diastolic essential hypertension [Group 1, aged 50.8+/-9.4 years (mean +/- SD)], participating in standardized Italian trials of antihypertensive drugs, and 506 elderly patients (group 2, age 71+/-7 years) with isolated systolic hypertension, participating in the European Syst-Eur trial.

RESULTS

The clinic-daytime blood pressure difference for the essential systolic and diastolic hypertensive patients (group 1) was 13.6+/-14.3 mmHg for systolic and 9.1+/-8.6 mmHg for diastolic blood pressure (P always < 0.01). This difference for the elderly patients with isolated systolic hypertension (group 2) was 21.2+/-16.0 mmHg for systolic and only 1.3+/-10.2 mmHg for diastolic blood pressure (P < 0.01 and P < 0.05, respectively). In both studies little or no systematic clinic-daytime difference could be observed for heart rate. The reproducibility of the clinic-daytime blood pressure difference, tested for 108 essential systolic and diastolic hypertensive patients from group 1 and 128 isolated systolic hypertensives from group 2, was invariably lower than that both of daytime and of clinic blood pressure values. Finally, the clinic-daytime blood pressure difference was progressively higher for increasing levels of clinic blood pressure and progressively lower for higher levels of ambulatory daytime blood pressure.

CONCLUSIONS

Thus, the clinic-daytime blood pressure difference has a limited reproducibility; depends not only on clinic but also on daytime average blood pressure, which means that its size is a function of the blood pressure criteria employed for selection of the patients in a trial; and is never associated with a systematic clinic-daytime difference in heart rate, which further questions its use as a reliable surrogate measure of the true pressor response induced in the patient by the doctor's visit.

Southwestern Internal Medicine Conference: difficult-to-treat hypertension

In this article, the author identifies the major causes of difficult-to-treat hypertension and provides guidelines for its management. The data were obtained from multiple clinical series of patients with hypertension resistant to therapy, reports of over-sensitivity to antihypertensive drugs, and the effects of anxiety-induced hyperventilation. As many as 15% of patients are resistant to antihypertensive therapy. Of the multiple possible causes for resistance, volume overload is the most common. Volume overload, in turn, is related to multiple factors, with inadequate diuretic therapy playing a major role. Many patients may experience tissue hypoperfusion when given usual doses of antihypertensive therapy, making their hypertension difficult to treat. In the author's experience, an even larger number of patients have psychosomatic symptoms, usually attributable to anxiety-induced hyperventilation, that often are blamed on their therapy. Therefore, hypertension may be difficult to treat for various reasons. When the cause is recognized, appropriate management almost always can be provided.

Clinical trials in chronic diseases

In spite of rather negative publicity on the crossover/self-controlled design for clinical trials in the early 1980s, a fair number of these studies were published in that period. Using these studies as examples, we try to give an overview of major advantages and disadvantages of crossover and parallel group studies. Strengths of the crossover versus the parallel design include: (1) elimination of between-subject variability of symptoms; (2) no need for large samples; (3) fewer ethical problems; and (4) subjects are able to express their preference for one of the compounds being given. Weaknesses include: (1) carryover effect from one treatment period into the other; and (2) time effect due to spontaneously evolving symptoms in a lengthy trial. Although routinely used for all types of therapies in phase I/II studies, the crossover/self-controlled design cannot be used in phase III/IV studies other than for symptomatic treatments of stable disease. Treatments of chronic diseases are directed primarily to the relief of persistent symptoms rather than the cure of a rapidly evolving symptomatology. These very aspects make them particularly suitable for crossover/self-controlled studies. Awareness of the weaknesses of clinical trials is especially important to clinical practitioners, who depend on reported clinical trials when making clinical decisions.

Clinical trials with ambulatory blood pressure monitoring: fewer patients needed? Syst-Eur Investigators

We have tested the concept that fewer patients are needed in trials of antihypertensive treatment if blood pressure is measured by ambulatory monitoring rather than by conventional sphygmomanometry. 233 patients (> or = 60 years old) with isolated systolic hypertension were randomly allocated placebo (n = 119) or active treatment (n = 114). Blood pressure measurements were compared by Wilcoxon's test and blood pressure profiles by ANOVA. With either method of measurement, the same number of patients (40 in each treatment group) was required to show a reduction after 1 year in clinic (13/8 mm Hg) or average blood pressure over 24 h (9/5 mm Hg). To detect that the decrease in systolic pressure was not steadily maintained through the day, 40 patients in each treatment group were needed for blood pressure profiles made up of 4-hourly or 2-hourly means and 60 for profiles of 1-hourly means. For diastolic pressure, the corresponding numbers were 80, 100, and more than the number of available patients, respectively. We conclude that parallel-group trials focusing on the average blood pressure over 24 h, rather than on conventionally measured blood pressure, cannot economise on sample size. Moreover, trials studying the full course of blood pressure throughout the day, require more--not fewer--patients than studies of only the conventional or average 24 h blood pressure.

The role of ambulatory monitoring of the blood pressure for assessment of antihypertensive agents

For many decades, the casual blood pressure (BP) has been the standard for assessing BP response to antihypertensive agents in clinical trials. Noninvasive ambulatory BP technology has improved vastly in the last 15 years and has been increasingly used in dose-response studies as well as efficacy trials. Through these studies we have learned that casual BP may not be representative of the average daily blood pressure, that it may be quite susceptible to observer bias, and that it may result in inaccurate calculation of the trough-to-peak ratio of an antihypertensive drug. Perhaps more importantly is that a large body of data now supports the superiority of average daily BP over that of the casual or clinic BP in predicting several indexes of hypertensive target organ damage. Thus, use of the ambulatory BP technique in antihypertensive trials yields BP data that are far less susceptible to improper diagnosis and are representative of the hypertensive burden that causes vascular disease.

Hypertension is not adequately controlled in hemodialysis patients

To examine the adequacy of hypertension control, we monitored the blood pressure (BP) of 53 hemodialysis patients who received treatment for hypertension. BP measurement using an ambulatory BP monitor began 1 hour before dialysis and continued every 30 to 60 minutes for 48 hours until the next dialysis. Diet, medications including antihypertensive drugs, and hemodialysis prescription were not changed during this study. Each patient had a mean of 68 BP measurements during the monitoring period. Mean (+/- SD) systolic and diastolic BP levels of all patients over 48 hours were 158.6 +/- 22.7 mm Hg and 88.7 +/- 16.6 mm Hg, respectively, without diurnal variations. In these, BP loads (the percentage of systolic BP exceeding 150 mm Hg and diastolic BP exceeding 90 mm Hg) were 58.4% and 39.4%, respectively, suggesting that hypertension was inadequately controlled for more than half of the study period. Eight patients (15%) maintained BP within normal ranges at all times. All patients lost weight (2.9 +/- 0.9 kg) at the end of dialysis by ultrafiltration. However, only 27 patients (51%) had a greater than 5% decrease in mean arterial BP post-dialysis, which returned to predialysis levels within 12 to 24 hours. Reduction of BP postdialysis was significantly more common among black patients (72%) than white patients (30%) (P less than 0.01). However, there was no difference in age, cause of kidney disease, amount of ultrafiltration, and BP loads between those whose BP decreased and those whose did not. BP monitoring was repeated in eight patients, 2 to 3 months after adjustment of their antihypertensive regimens.(ABSTRACT TRUNCATED AT 250 WORDS)

Therapeutic Issues in the Evaluation and Treatment of the Hypertensive Patient: White Coat Hypertension and Once Daily Dosing of Antihypertensive Agents

Pharmacists are an invaluable resource of drug and other treatment information for the primary provider because of their skills in drug literature evaluation and retrieval. The implementation of a home blood pressure monitoring program at the HMO of Delaware has allowed the establishment of excellent relations between medical, nursing, and pharmacy personnel and has allowed the pharmacist to become involved in the decision-making process for many hypertensive patients.

Prevention of coronary heart disease in Finland--application of the population strategy

The North Karelia Project was the first population-based cardiovascular disease prevention programme. Even though it achieved, as compared to the reference population, a sizeable reduction in smoking and small effect in blood pressure and serum cholesterol levels, the effect on coronary and cardiovascular mortality of the programme remains equivocal. This is mainly due to shortcomings in the original study design and unanticipated start of the national decline in coronary mortality at the same time with the programme. North Karelia Project contributed, however, to the initiation of national activities in the prevention of cardiovascular disease. These have produced a favourable trend in lipids in the whole Finnish population. The recommendations and activities by national authorities and organizations have suffered, until recently, from orientation towards screening and individual risk factors. The success in North Karelia in early 1970's in the reduction of smoking has still not occurred nationally. Further emphasis is needed in the population approach and in the integration of preventive activities into the community and legislation.

Ambulatory blood pressure measurement in type 2 diabetic patients: methodological aspects

Ambulatory blood pressure was measured over 24 h on two occasions in 29 Type 2 diabetic patients age 65 (range 52-74) years, and the reproducibility compared with that of ordinary clinic measurements recorded by Hawskley's random zero sphygmomanometer. The variability of the difference between blood pressure measurements on the two occasions was twice as large for clinic measurement as for ambulatory measurement (2p less than 0.01). If applied to clinical trials this would allow a fourfold reduction of patient numbers without losing test power. In the group of patients treated with antihypertensive medication (n = 16) the spontaneous decline in blood pressure after leaving the hospital proved to be most prominent in those patients with the highest clinic blood pressure, a phenomenon with importance for the management of hypertension. The individual difference between clinic measurements and ambulatory day-time measurements from the same day was unpredictable. Ambulatory blood pressure measurement in the outpatient clinic may be a practicable approach for optimizing antihypertensive treatment in Type 2 diabetic patients.

Managing the problem patient

Anxiety, overtreatment, inappropriate combination therapy, and noncompliance are all characterized as prevalent etiologic factors in so-called resistant hypertension. But perhaps the most common problem that expresses itself as resistant hypertension is failure to adequately control intravascular volume. The key point is that a cause for resistance is almost always discoverable.

Ambulatory blood pressure monitoring in the evaluation of drug efficacy

Conventional clinic measurement of blood pressure is influenced by many factors that make the technique unsuitable for the assessment of antihypertensive drug efficacy. The major drawback of conventional measurement is that it cannot indicate the duration of drug effect or the influence of antihypertensive drugs on nocturnal blood pressure. Noninvasive 24-hour ambulatory blood pressure measurement has a number of advantages over conventional measurement: it provides a profile of blood pressure over the 24-hour period; it detects white coat responders; it is free of regression to the mean and the placebo response, thereby making it possible to consider efficacy studies which need not have a placebo phase; it enables considerably more observations than is possible with clinic measurement by increasing the power of studies, which may reduce significantly the numbers of patients needed for antihypertensive drug studies. Twenty-four-hour ambulatory blood pressure measurement offers the opportunity to study antihypertensive drugs in fewer patients with greater accuracy than is possible with conventional clinic measurement and should be a mandatory requirement for such studies.

[The significance of 24-hour blood pressure monitoring in the diagnosis and therapy of arterial hypertension]

The use of ABPM allows an improved assessment of blood pressure (BP) and therefore of the individual cardiovascular risk. It is able to identify patients who truly need therapy more exactly. Mostly patients with white coat hypertension who don't need therapy are identified. Furthermore, ABPM correlates more closely to target organ damage and to cardiovascular morbidity and mortality. This may be helpful to treat especially those patients who truly need therapy. BP exhibits a typical circadian rhythm with the highest values during the early morning hours and a decline during the night. A change of the day/night rhythm during shift work leads to an adaptation of BP rhythm. The early morning rise of BP and heart rate is accompanied by hemodynamic, rheological and biochemical alterations, which together may contribute to the increased frequency of vascular complications during the morning hours. The nightly decline of BP is often absent in patients with secondary hypertension and cardiac or renal organ damage. A lack of the nocturnal BP decline should therefore lead to further patients' evaluation. Elevated nocturnal BP seems to worsen the prognosis. ABPM offers better individual control of BP in patients on treatment and therefore is helpful to optimize the treatment. A more exact individual BP control during the awakening and sleeping period is possible as well as an avoidance of overtreatment. Patients could be protected both from prescription of too many drugs and from lowering BP too much. A further advantage lies in an improved control of patients with nocturnal hypertension.

Comparison of the antihypertensive efficiency of nitrendipine, metoprolol, mepindolol and enalapril using ambulatory 24-hour blood pressure monitoring

In a randomized 6-month study of 201 patients, the antihypertensive efficiency of the calcium antagonist nitrendipine, the beta 1-selective blocker metoprolol, mepindolol, the beta blocker with intrinsic activity and the angiotensin-converting enzyme inhibitor enalapril were compared as monitored by 24-hour ambulatory blood pressure (BP) measurements. The study was designed so that a comparable decrease in casual BP values was obtained with all 4 drugs. If normotension was not achieved with monotherapy, a diuretic also was administered. Pretreatment casual BP and mean 24-hour ambulatory BP values did not differ between the 4 groups. Normotension as assessed by casual BP measurements was observed in all 4 groups after 6 months of therapy, there being no significant differences between the groups. However, significantly more diuretics were required in the mepindolol (n = 14) and in the enalapril (n = 20) groups compared to the nitrendipine (n = 5) and metoprolol (n = 7) groups. Despite comparable casual BP control, the 4 groups differed significantly in their mean 24-hour measurements. The greatest systolic and diastolic BP decreases were seen in the metoprolol group. Metoprolol was also the most effective drug in decreasing the frequency of systolic pressure peaks greater than 180 mm Hg. Both beta blockers and enalapril significantly decreased the morning BP increase compared to the values before treatment, while nitrendipine did not. These data show that casual BP measurement is not a good predictor of 24-hour BP in patients taking hypertensive therapy. Despite an equal degree of "office" BP control, different antihypertensive regimens do not confer the same degree of "nonoffice" BP control.

Clinical evaluation of a novel ambulatory automatic blood pressure monitoring system

Reliability and reproducibility of a new automatic ambulatory blood pressure recorder were tested on 31 subjects (18 normotensives and 13 hypertensives). Of 3688 recordings, 1424 measurements were cross-checked with a sphygmomanometer in standing or sitting position at the beginning and at the end of a twenty-four hour monitoring period. In the normotensive subjects cross-checkings were performed also during a treadmill exercise stress test. Analysis of variance did not indicate statistical differences between the two types of measurement (p greater than 0.09 for systolic and p greater than 0.62 for diastolic), and a significant linear correlation was found at rest (r = 0.99, p less than 0.001 for systolic and r = 0.98, p less than 0.001 for diastolic pressure). During the effort test the device was unable to correctly measure blood pressure values after the first step. During the twenty-four hour monitoring period only 1.1% of the preprogrammed measurements were lost for each subject. The recorder seems to be a suitable and reliable tool for automatic blood pressure monitoring.

Noninvasive ambulatory blood pressure monitoring in patients with recently detected systemic hypertension

Noninvasive ambulatory blood pressure monitoring and Doppler echocardiography were used in a recent study evaluating persons aged 18 to 50 years who were initially found to have mild hypertension by casual blood pressure determination. Ambulatory blood pressure recordings were performed on a day of usual activity in 54 subjects; a subgroup of 24 patients had evaluation of left ventricular dimensions and diastolic filling patterns by Doppler echocardiography. Average ambulatory systolic pressures of 42% of subjects were greater than or equal to 130 mm Hg. Only 35% had average diastolic pressures greater than or equal to 85 mm Hg, and 57% had either systolic or diastolic pressures greater than or equal to 130/85 mm Hg. Correlation between casual and ambulatory pressures was not significant. No subject had left ventricular hypertrophy determined by echocardiography. Abnormal left ventricular diastolic filling was noted in 38% of those patients with average ambulatory pressures greater than or equal to 130/85 mm Hg, but in no patients with average pressures less than 130/85 mm Hg (p less than 0.05). These results suggest that ambulatory blood pressure monitoring may be a specific method for detecting those patients with mild hypertension who may have early and potentially reversible cardiac abnormalities.

The relationship between casual and ambulatory blood pressure in essential hypertension: the influence of work, duration of hypertension and antihypertensive treatment

Casual blood pressure (BP) and ambulatory BP (mean 24-h BP) were determined in 23 untreated patients with essential hypertension and in 11 normotensive healthy control subjects. Mean 24-h BP was significantly lower than casual BP in patients with essential hypertension, but not in control subjects. This was demonstrated in the patients who did not work during the ambulatory BP monitoring and in the patients with newly recognized hypertension, whereas no differences were revealed either in the patients who went to work or had a known duration of hypertension longer than 6 months. The size of the difference between casual BP and mean 24-h BP was unaffected by antihypertensive therapy with metoprolol and also individually reproducible. An accordance between casual and ambulatory BP measurements in evaluation of the efficacy of antihypertensive treatment was found in 75% of the patients. Casual BP and mean 24-h BP were weakly correlated both before and during antihypertensive treatment. It is concluded that the higher casual BP than ambulatory BP in essential hypertension may be a specific characteristic of the disease. Both work and known duration of hypertension longer than 6 months eliminate the difference between casual ambulatory BP in essential hypertension. Ambulatory BP monitoring seems to be superior to casual BP measurements in the evaluation of antihypertensive treatment.

Hypertension costs: source, evolution and impact of cost-containment measures in various health-care systems

As a consequence of the high prevalence of hypertension in most countries, the management of this disease generates costs which are only justified if the beneficial effects of the reduced blood pressure can be achieved by the long-term control of blood pressure in compliant patients. The expenditure includes not only the cost of drugs, but also the cost of visits to physicians and various supplementary examinations. Whereas these latter cost items are exclusively dependent on the physicians who order them, the costs of the drugs are dependent on the physician's choice and also on the drug-pricing mechanisms, which are complex, variable from one country to another and dependent on economic choices, as well as on medical parameters. The selection of drugs should be tailored to each individual patient and based on reliable medical evidence. However, the consequences of the choice of drugs will be very much influenced by the pricing procedures applied in each country. Whereas improvement in the quality of hypertension management will increase the efficacy of the medical intervention, cost-containment measures might make it even more efficient. These measures can be initiated by the physicians themselves, in regard to the number of visits and the choice of supplementary examinations. They can also be generated by incentive measures coming from the different health-care systems (state or private insurance schemes). Such measures should prevent patients being deprived of access to the most modern methods of treatment, including examinations and drugs, while at the same time aiming at eliminating unnecessary examinations and inappropriate choice of drugs. The impact of cost-containment measures, when implemented, should be monitored in regard to both the quality of care (permanent blood pressure control of treated patients, without impairment of their quality of life) and the existence of social inequalities in the access to optimal health-care.