Evaluation of self-measured home vs. clinic intra-arterial blood pressure

Smoking and overweight associated with masked uncontrolled hypertension: a Hypertension Optimal Treatment (HOT) Sub-Study

PURPOSE

The Hypertension Optimal Treatment (HOT) Study investigated the relationship between target office diastolic blood pressure (BP) ≤80, ≤85 or ≤90 mmHg and cardiovascular morbidity and mortality in 18,790 patients aged 50-80 years. The home BP sub-study enrolled 926 patients and the aim was to clarify whether the separation into the BP target groups in the office prevailed in the out-of-office setting. The present study aimed to identify variables that characterised masked uncontrolled hypertension (MUCH) and white coat uncontrolled hypertension (WUCH).

MATERIAL AND METHODS

The sub-study participants took their home BP when office BP had been up titrated. The cut-off for normal or high BP was set to ≥135/85 mmHg at home and ≥140/90 mmHg in the office. We analysed data by using multivariate and stepwise multivariate logistic regression with home and office BP combinations as the dependent variables.

RESULTS

WUCH was associated with lower body mass index (BMI) (odds ratio (OR) 0.92, 95% confident intervals (CIs) 0.88-0.96, p < 0.001). MUCH was associated with smoking (OR 1.89, 95% CIs 1.25-2.86, p = 0.0025) and with lower baseline heart rate (OR 0.98, 95% CIs 0.97-0.99, p = 0.03) and higher BMI (OR 1.03, CIs 1.00-1.06, p = 0.04). MUCH remained associated with smoking (OR 2.76, 95% CIs 1.76-4.35, p < 0.0001) also when using ≥140/90 mmHg as the cut-off for both home and office BP. MUCH was also associated with higher BMI (OR 1.05, 95% CIs 1.01-1.09, p = 0.009) while WUCH was associated with lower BMI (OR 0.93, 95% CIs 0.90-0.97, p = 0.0005) when using ≥140/90 mmHg as a cut-off.

CONCLUSION

Our data support that 'reversed or masked' treated but uncontrolled hypertension (MUCH) is common and constitutes about 25% of treated hypertensive patients. This entity (MUCH) is rather strongly associated with current smoking and overweight while uncontrolled white coat (office) hypertension (WUCH) is associated with lower BMI.

Self-monitoring of blood pressure should be used in clinical trials

The number of studies of the efficacy of drugs in hypertension and of their effects on morbidity and mortality continues to be large. Traditionally such studies were carried out by measuring the blood pressure (BP) in the office. Recently, there has been an increasing use of other approaches, such as self-measurement. The advantages of this technique may be the achievement of greater precision of measurement, explained by elimination of the white-coat effect, reduction in placebo effect and reduction in variability of BP. Some have even noted a greater reproducibility than using ambulatory BP monitoring. We now have available reference values and normal ranges for self-BP monitoring. The feasibility and the limitations of self-BP measurement are also known. Self-measurement allows multiple recordings of BP over the short term as well as over the long term. Moreover, the compliance of this technique is satisfying. The analysis of the data requires precise recommendations. One cannot refer to trough : peak ratio, which is used in ambulatory recordings. However, other methods of analysis such as evening BP : morning BP ratio or measures taken after taking treatment are useful. The number of subjects needed for a study is much smaller than in a study performed using office measurements for a similar or better statistical power. Such a method has a higher predictive value than clinic measurement both for study of end organ damage and for morbidity and mortality. Finally home measurement is much less costly. In conclusion, provided one uses validated equipment and if one follows recommendations for each measurement and for the succession of measurements, then self-measurement of BP at home seems a useful and practical tool for therapeutic trials.

[Variations in the prevalence and patient profile of white-coat syndrome, according to its definition using self-measurement of blood pressure at home]

OBJECTIVE

To calculate the prevalence of white-coat syndrome (WCS) in patients with hypertension, comparing the two most common definitions and their effect on the profile of the patient with WCS.

DESIGN

Cross-sectional, descriptive study.Setting. Urban health centre.Patients. Hypertense patients selected by simple randomised sampling from among those included in the hypertension programme.

MEASUREMENTS

Clinical blood pressure (CBP) from the previous year was collected. Home blood pressure (HBP) was measured by the patient with an electronic sphygmomanometer. Age, sex, further tests (analysis and electrocardiogram) and other clinical features were also recorded. WCS was defined as when CBP was above/equal to 140/90 mmHg and HBP was under 135/85 mmHg or when the difference between CBP and HBP was more than/equal to 20 mmHg systolic and/or 10 mmHg diastolic pressure.

RESULTS

In 154 hypertense patients (60.4% women) between 38 and 92 years old, mean CBP (141.1/85.3) was higher than mean HBP (136.8/79.8). WCS prevalence varied (p = 0.001), depending on the definition used (20.1% and 36.4%). The systolic and diastolic mean CBP of the last year were higher in those patients with WCS (p < 0.001 for diastolic pressure). The profile of hypertense patients with WCS varied according to the definition used.

CONCLUSIONS

WCS is common in hypertense patients treated in Primary Care and may condition an inadequate assessment of the degree of blood pressure monitoring. As the way of defining WCS conditions its prevalence, its profile and clinical decision-taking, it is essential to agree a uniform definition for practical use.

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)

Comparison of self-reported home blood pressure measurements with automatically stored values and ambulatory blood pressure

AIMS

To evaluate accuracy of patient-reported home blood pressure measurements (HBPM) when compared to real HBPM and their agreement with 12-h daytime ambulatory blood pressure monitoring (ABPM).

MAJOR FINDINGS

Self-reported HBPM were compared to stored values of a fully automated, oscillometric blood pressure monitor with integrated memory device and 12-h daytime ambulatory monitoring in 54 patients. In most patients (n = 46, 85%) mean reported systolic or diastolic versus real HBPM differed by no more than 4 mmHg. In eight mostly uneducated patients (15%, 95% confidence interval, CI, 7-27%) means of reported and real HBPM differed by more than 4 mmHg (range 5-28 mmHg for systolic and 0-11 mmHg for diastolic blood pressure). Systolic agreement between self-reported HBPM and 12-h daytime ABPM was better for patients reporting > or = 80% than for patients reporting < 80% of measurements correctly (mean systolic difference 0 +/- 19 versus 5 +/- 14 mmHg, respectively), whereas the opposite was true concerning agreement of diastolic blood pressure values (mean diastolic difference -6 +/- 10 and -1 +/- 9 mmHg, respectively).

CONCLUSION

Inadequate conclusions due to poor reporting accuracy of HBPM are possible, especially in less educated patients. Thus, ABPM or automatically stored HBPM may be preferable to self-reported HBPM in these patients.

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.

Hypertension optimal treatment (HOT) study: home blood pressure in treated hypertensive subjects

The Hypertension Optimal Treatment Study is a prospective trial conducted in 26 countries. The aims are to (1) evaluate the relationship between three levels of target office diastolic blood pressure (BP) (< or = 80, < or = 85, or < or = 90 mm Hg) and cardiovascular morbidity and mortality in hypertensive patients and (2) examine the effects on cardiovascular morbidity and mortality of 75 mg aspirin daily versus placebo. A total of 19,193 patients between 50 and 80 years of age had been randomized by the end of April 1994. Treatment was initiated with felodipine 5 mg daily, and additional therapy was given in accordance with a set protocol. The present substudy of 926 patients performed in nine countries aimed to (1) compare home with office BP in a representative subsample of the HOT population after the titration of treatment was completed and (2) clarify whether the separation into the target groups could be expanded into the out-of-office setting. The differences between office and home measurements in diastolic BP of 0.2 mm Hg (SD, 9; 95% confidence interval, -0.36 to 0.81; P=.40) and systolic BP of 0.5 mm Hg (SD, 15; 95% confidence interval, -0.53 to 1.46; P=.21) were not significant. The group differences in home BP were 1.9 mm Hg (< or = 80 versus < or = 85) and 1.2 mm Hg (< or = 85 versus < or = 90) for diastolic BP (F=11.69; ANOVA, P<.0001) and 2.6 and 2.1 mm Hg for systolic BP (F=8.44, P=.0002). Thus, office and home BPs measured with the same semiautomatic device are comparable in treated hypertensive subjects in the HOT Study, and the separation into the target groups based on office readings prevails at home.

Sympathetic nervous system involvement in essential hypertension: increased platelet noradrenaline coincides with decreased beta-adrenoreceptor responsiveness

Platelet catecholamine content may reflect integrated plasma catecholamine concentrations over time. The present study aimed at examining sympathetic nervous system (SNS) involvement in essential hypertension by assessing platelet noradrenaline (NA) and typically beta-adrenoreceptor mediated responses to adrenaline (A) infusion as indices of sympathetic tone. Healthy white men were recruited by public advertising and screening (mean +/- SD): Hypertensives (n = 13, sitting blood pressure [BP] 153 +/- 13/106 +/- 7 mmHg, age 34 +/- 5 years, weight 83 +/- 10 kg) were compared to normotensives (n = 13, sitting BP 114 +/- 9/75 +/- 9 mmHg, age 30 +/- 6 years [n.s.], weight 82 +/- 9 kg [n.s.]). Loss of platelet granular contents (including NA) prior to analysis was minimized by studying young subjects (age range 20-40 years, minimal atherosclerosis), using arterial blood sampling, and processing blood immediately. These procedures resulted in plasma beta-thromboglobulin and platelet factor 4 levels which were not significantly different between groups. Sympathetic activation resulting from stress was minimized by not labelling subjects as either hypertensive or normotensive. Mean arterial platelet NA content was significantly higher in hypertensives (64 +/- 31 pg/mg of platelet weight) compared to normotensives (43 +/- 20 pg/mg, p < 0.05) both at baseline and following 35% expansion of the circulating platelet pool by A infusion (p < 0.05) and correlated with arterial NA in the hypertensives (r = 0.79, p < 0.002) but not in the normotensives (r = 0.04, n.s.). Similar increases in platelet and plasma A during infusion in both groups suggest unchanged platelet uptake capacity and plasma clearance in the hypertensive group.(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular mass and cardiovascular reactivity in young men

The relation between left ventricular wall thickness and mass, arterial plasma catecholamines, and blood pressure at rest and during a mental arithmetic challenge and a cold pressor test was examined in 69 healthy men 19 years of age. The subjects were recruited from the 1st (n = 21), 50th (n = 26), and 99th (n = 22) percentiles in mean blood pressure. All underwent echocardiography to determine mean wall thickness and left ventricular mass. Continuous intra-arterial blood pressure, electrocardiogram, and arterial sampling of plasma catecholamines were performed after 30 minutes of supine rest, during a 5-minute mental arithmetic challenge, and during a 1-minute cold pressor test. Stepwise multiple-regression analyses considering mean wall thickness and left ventricular mass as the dependent variables were applied. Intra-arterial systolic blood pressure (r = .54, P < .0001) and arterial plasma epinephrine (r = .31, P = .009) after 30 minutes of supine rest were the only independent explanatory variables of mean wall thickness (multiple R2 = .33, P < .0001). Blood pressure at screening and during mental stress and cold pressor tests were not independent explanatory variables. The present study suggests that resting arterial blood pressure and plasma epinephrine may be of importance for development of left ventricular hypertrophy.