Diagnosis of hypertension using home or ambulatory blood pressure monitoring: comparison with the conventional strategy based on repeated clinic blood pressure measurements

Assessment of self‐monitoring of blood pressure in the diagnosis of isolated clinic hypertension

BACKGROUND

There are no studies assessing cardiovascular morbidity, morality in patients with isolated clinical hypertension (ICH) with self-blood pressure monitoring (SBPM).

OBJECTIVES

To determine the value of SBPM in the diagnosis of ICH.

METHODS

Cohort study. New hypertensive and normotensive patients 15-75 years, without cardiovascular events history.

VARIABLES

Oriented anamnesis hypertension; blood pressure measurements (BP): clinical BP, SBPM and ambulatory BP monitoring (ABPM); evaluation of target organ damage (TOD); electrocardiogram; retinography and microalbuminuria (MA).

RESULTS

One hundred and thirty-five patients, 95 hypertensive (62.1% males; mean age 59.08+/-16.8 years), 40 normotensive (37.5% males; mean are 56.32+/-10.22 years). BP measurements (mmHG) in normotensives vs hypertensives: clinical BP, 125.36/76.74 vs 149.81/87.86 mmHg (p<0.0001) and SPPM, 114.90/69.96 vs 142.06/86.31 (p<0.0001). Twenty-four-hour ABPM: 135.41/81/81.74. Prevalence of TOD in hypertensive: 23.10% left ventricular hypertrophy (LVH), sustained hypertension (SH): clinic BP, 149.88/86.34 vs 152.51/89.55 (p>0.10); SBPM: 147.895/88.95 vs 128.17/79 (p<0.0001) and ABPM, 141.72/88.22 vs 131.66/80 (p=0.053 for systolic). TOD in SH vs ICH: LVH, 24.6% vs 19.2% (p=0.814); exudates or haemorrhages, 7.7% vs 9.8% (p=0.580). The risk of an occurrence of any TOD in ICH patients is lower for 125/80 (OR=2.5).

CONCLUSIONS

VAMPAHICA will provide information about value SBPM in the diagnosis of ICH. Advanced retinopathy is relative frequent in ICH patients. If TOD is accepted as a surrogate endpoint, the diagnostic values of ICH will be probably decreased.

Reproducibility of home and ambulatory blood pressure in children and adolescents

OBJECTIVE

To evaluate the reproducibility of blood pressure measured at home (HBP) in comparison with ambulatory (ABP) and clinic blood pressure (CBP) in children and adolescents.

PARTICIPANTS AND METHODS

Individuals aged 8-17 years who had been referred for elevated CBP were included. CBP was measured at two visits, HBP on 5 days and ABP for 24 h. A second session including all the above measurements was performed after 8 weeks. The reproducibility of CBP (second visit of each session), HBP (average of days 2-5 of each session) and ABP (average 24-h, awake and asleep) was quantified using test-retest correlations coefficients (r) and the standard deviation of differences (SDD) between repeated measurements.

RESULTS

Sixteen individuals were included [mean age 13.3+/-2.9 (SD)] years, range 8-17, nine boys]. According to Task Force CBP criteria, eight were classified as hypertensives, three as high normal and five as normotensives. The reproducibility of HBP (systolic/diastolic r, 0.74/0.82, SDD 7.0/4.3) was superior to that of CBP (r, 0.63/0.80, SDD 10.4/6.3). However, ABP appeared to provide the most reproducible values (r, 0.87/0.84, SDD 5.5/4.3 for 24-h ABP; r, 0.85/0.76, SDD 5.9/5.0 for awake; r, 0.76/0.79, SDD 7.0/5.0 for asleep ABP). Aspects of the diurnal ABP variation were poorly reproducible (r, 0.62/0.14, SDD 6.8/5.5 for awake-asleep ABP difference; r, 0.55/0.26, SDD 0.07/0.11 for awake : asleep ratio).

CONCLUSION

These data suggest that in children and adolescents home blood pressure measurements are more reproducible than clinic measurements. However, 24-h ambulatory monitoring appears to provide the most reproducible blood pressure values.

Morning blood pressure surge: the reliability of different definitions

Preliminary evidence suggests that the morning surge (MS) in blood pressure (BP) is an independent predictor of cerebrovascular disease. However, the optimal definition of MS is uncertain. To compare the reproducibility of several MS definitions used in the literature, 132 untreated hypertensives were assessed with ambulatory BP monitoring twice, 2 weeks apart. Five MS definitions were compared. MS-1: the average BP of the first hour after rising minus the average BP of the first hour before rising; MS-2: BP 2 h after rising minus that of 2 h before rising; MS-3: BP 3 h after rising minus that of 3 h before rising; MS-4: BP 2 h after rising minus the average BP during sleep; MS-5: BP 2 h after rising minus the average BP of 3 consecutive readings, centered on the lowest reading during sleep. The reproducibility of each MS definition was assessed using the concordance correlation coefficient (CCC), the standard deviation of differences (SDD) and the coefficient of variation (CV) between repeated MS assessments, and the agreement in detecting "surgers," defined as subjects at the top quartile (Q4) of the MS distribution. CCCs were 0.20/0.30, 0.43/0.45, 0.53/0.51, 0.51/0.47, and 0.46/0.48 (systolic/diastolic) for MS-1 to MS-5 respectively; SDDs were 14.3/11.4, 12.1/9.9, 11.2/9.5, 10.3/8.2, and 11.9/9.8, respectively; CVs were 0.49/0.57, 0.44/0.39, 0.37/0.35, 0.36/0.31, and 0.27/0.24, respectively; and the agreement in detecting "surgers" was 69%/70%, 71%/76%, 75%/75%, 81%/83%, and 74%/75%, with kappa of 0.18/0.20, 0.23/0.36, 0.33/0.33, 0.49/0.53 and 0.29/0.31, respectively. There are important differences in the reproducibility of MS calculated by different methods. MS4 appears to provide the most reproducible definition of MS.

Call to action on use and reimbursement for home blood pressure monitoring: a joint scientific statement from the American Heart Association, American Society of Hypertension, and Preventive Cardiovascular Nurses Association

Home blood pressure monitoring (HBPM) overcomes many of the limitations of traditional office blood pressure (BP) measurement and is both cheaper and easier to perform than ambulatory BP monitoring. Monitors that use the oscillometric method are currently available that are accurate, reliable, easy to use, and relatively inexpensive. An increasing number of patients are using them regularly to check their BP at home, but although this has been endorsed by national and international guidelines, detailed recommendations for their use have been lacking. There is a rapidly growing literature showing that measurements taken by patients at home are often lower than readings taken in the office and closer to the average BP recorded by 24-hour ambulatory monitors, which is the BP that best predicts cardiovascular risk. Because of the larger numbers of readings that can be taken by HBPM than in the office and the elimination of the white-coat effect (the increase of BP during an office visit), home readings are more reproducible than office readings and show better correlations with measures of target organ damage. In addition, prospective studies that have used multiple home readings to express the true BP have found that home BP predicts risk better than office BP (Class IIa; Level of Evidence A). This call-to-action article makes the following recommendations: (1) It is recommended that HBPM should become a routine component of BP measurement in the majority of patients with known or suspected hypertension; (2) Patients should be advised to purchase oscillometric monitors that measure BP on the upper arm with an appropriate cuff size and that have been shown to be accurate according to standard international protocols. They should be shown how to use them by their healthcare providers; (3) Two to 3 readings should be taken while the subject is resting in the seated position, both in the morning and at night, over a period of 1 week. A total of >/=12 readings are recommended for making clinical decisions; (4) HBPM is indicated in patients with newly diagnosed or suspected hypertension, in whom it may distinguish between white-coat and sustained hypertension. If the results are equivocal, ambulatory BP monitoring may help to establish the diagnosis; (5) In patients with prehypertension, HBPM may be useful for detecting masked hypertension; (6) HBPM is recommended for evaluating the response to any type of antihypertensive treatment and may improve adherence; (7) The target HBPM goal for treatment is <135/85 mm Hg or <130/80 mm Hg in high-risk patients; (8) HBPM is useful in the elderly, in whom both BP variability and the white-coat effect are increased; (9) HBPM is of value in patients with diabetes, in whom tight BP control is of paramount importance; (10) Other populations in whom HBPM may be beneficial include pregnant women, children, and patients with kidney disease; and (11) HBPM has the potential to improve the quality of care while reducing costs and should be reimbursed.

Diagnosis of hypertension in children and adolescents based on home versus ambulatory blood pressure monitoring

OBJECTIVE

To investigate the usefulness of home blood pressure measurements in comparison with ambulatory monitoring in the diagnosis of sustained, white-coat hypertension and masked hypertension in children and adolescents.

SUBJECTS AND METHODS

One hundred and two subjects, referred for elevated blood pressure, were assessed with clinic (two visits), home (6 days) and awake ambulatory blood pressure measurements [64 boys, mean age 12.8 +/- 2.9 (SD) years, range 6-18 years].

RESULTS

Office hypertension was diagnosed in 38 subjects, ambulatory hypertension in 31 and home hypertension in 23 (P = 0.07). On the basis of clinic and ambulatory blood pressure, 52% of subjects were normotensive, 20% hypertensive, 18% had white-coat hypertension and 11% masked hypertension, whereas on the basis of clinic and home blood pressure, 55, 15, 23 and 8%, respectively. There was an agreement between ambulatory and home blood pressure in the diagnosis of hypertension in 82 cases (80%). When a 5-mmHg gray zone of diagnostic uncertainty was applied above and below the diagnostic thresholds, there were only eight cases with clinically important disagreement. By taking ambulatory blood pressure as the reference method for the diagnosis of hypertension, the sensitivity, specificity and positive and negative predictive values of home blood pressure were 55, 92, 74 and 82%, respectively, for the diagnosis of white-coat hypertension 89, 92, 70 and 98%, respectively, and for masked hypertension 36, 96, 50 and 93%, respectively.

CONCLUSION

In children and adolescents, there is a reasonable agreement between home and ambulatory blood pressure measurements as diagnostic methods in hypertension. Home blood pressure appears to be a useful diagnostic test in this population, particularly for the detection of white-coat hypertension.

World Hypertension Day and global awareness

The World Health Organization attributes hypertension, or high blood pressure, as the leading cause of cardiovascular mortality. The World Hypertension League (WHL), an umbrella organization of 85 national hypertension societies and leagues, recognized that more than 50% of the hypertensive population worldwide are unaware of their condition. To address this problem, the WHL initiated a global awareness campaign on hypertension in 2005 and dedicated May 17 of each year as World Hypertension Day (WHD). Over the past three years, more national societies have been engaging in WHD and have been innovative in their activities to get the message to the public. In 2007, there was record participation from 47 member countries of the WHL. During the week of WHD, all these countries -- in partnership with their local governments, professional societies, nongovernmental organizations and private industries -- promoted hypertension awareness among the public through several media and public rallies. Using mass media such as Internet and television, the message reached more than 250 million people. As the momentum picks up year after year, the WHL is confident that almost all the estimated 1.5 billion people affected by elevated blood pressure can be reached. The success of WHD is due to the enthusiasm and voluntary action of multiple stakeholders from every member country.

Call to action on use and reimbursement for home blood pressure monitoring: a joint scientific statement from the American Heart Association, American Society Of Hypertension, and Preventive Cardiovascular Nurses Association

Home blood pressure monitoring (HBPM) overcomes many of the limitations of traditional office blood pressure (BP) measurement and is both cheaper and easier to perform than ambulatory BP monitoring. Monitors that use the oscillometric method are currently available that are accurate, reliable, easy to use, and relatively inexpensive. An increasing number of patients are using them regularly to check their BP at home, but although this has been endorsed by national and international guidelines, detailed recommendations for their use have been lacking. There is a rapidly growing literature showing that measurements taken by patients at home are often lower than readings taken in the office and closer to the average BP recorded by 24-hour ambulatory monitors, which is the BP that best predicts cardiovascular risk. Because of the larger numbers of readings that can be taken by HBPM than in the office and the elimination of the white-coat effect (the increase of BP during an office visit), home readings are more reproducible than office readings and show better correlations with measures of target organ damage. In addition, prospective studies that have used multiple home readings to express the true BP have found that home BP predicts risk better than office BP (Class IIa; Level of Evidence A). This call-to-action article makes the following recommendations: (1) It is recommended that HBPM should become a routine component of BP measurement in the majority of patients with known or suspected hypertension; (2) Patients should be advised to purchase oscillometric monitors that measure BP on the upper arm with an appropriate cuff size and that have been shown to be accurate according to standard international protocols. They should be shown how to use them by their healthcare providers; (3) Two to 3 readings should be taken while the subject is resting in the seated position, both in the morning and at night, over a period of 1 week. A total of >or=12 readings are recommended for making clinical decisions; (4) HBPM is indicated in patients with newly diagnosed or suspected hypertension, in whom it may distinguish between white-coat and sustained hypertension. If the results are equivocal, ambulatory BP monitoring may help to establish the diagnosis; (5) In patients with prehypertension, HBPM may be useful for detecting masked hypertension; (6) HBPM is recommended for evaluating the response to any type of antihypertensive treatment and may improve adherence; (7) The target HBPM goal for treatment is <135/85 mm Hg or <130/80 mm Hg in high-risk patients; (8) HBPM is useful in the elderly, in whom both BP variability and the white-coat effect are increased; (9) HBPM is of value in patients with diabetes, in whom tight BP control is of paramount importance; (10) Other populations in whom HBPM may be beneficial include pregnant women, children, and patients with kidney disease; and (11) HBPM has the potential to improve the quality of care while reducing costs and should be reimbursed.

The optimal schedule for self-monitoring of blood pressure by patients at home

The optimal schedule for home blood pressure monitoring should represent the usual level of home blood pressure, give a reproducible value, and have prognostic ability. Therefore, outcome studies, as well as short-term trials assessing the reproducibility of home blood pressure, its stability over time and its relationship with ambulatory blood pressure should be taken into account. A review of this evidence suggests that the optimal schedule should be based on 12-14 measurements, and even more measurements up to 25 are desirable. Morning and evening measurements should be obtained, with at least duplicate measurements per occasion. Measurements on the initial day should preferably be discarded.

Proportion of isolated clinical hypertension in primary care settings. Comparison of target organ damage in patients with isolated clinical hypertension and patients with sustained arterial hypertension

The aim of this study was to determine the proportion of isolated clinical hypertension (ICH) in newly diagnosed hypertensive patients, and to compare the incidence of target organ damage (TOD) in ICH and sustained hypertension patients. Participants. In a multi-centre study involving 14 primary care centres in Girona, Spain, 140 researchers recruited 214 newly diagnosed hypertensive patients 15-75 years of age, without history of cardiovascular events. Period of study. 2004-6. Method. Self-blood pressure monitoring (SBPM) and ambulatory blood pressure monitoring (ABPM). Evaluation. Anamnesis including blood pressure, physical examination and analysis (creatinine, albumin/creatinine index), electrocardiogram (left ventricular hypertrophy) and retinography (fundus damage). Results. In 129 (60.3%) subjects with sustained hypertension and 85 (39.7%) with ICH, no significant differences were found relative to gender, age, body mass index or blood pressure (155/90 vs 154/90 mmHg, respectively). Cholesterol levels were significant differences between both groups (5.97 mmol/l in sustained hypertension vs 5.64 mmol/l in ICH, p = 0.029). The proportion of ICH was approximately 40%. TOD incidence in sustained hypertensives was similar to that of ICH patients.

Home blood pressure normalcy in children and adolescents: the Arsakeion School study

OBJECTIVE

There is evidence that home blood pressure (BP) is being used in clinical practice for the assessment of out-of-office blood pressure in children. However, there is no information on the normal range of home BP in this population. This prospective school-based study was designed to investigate the normal range of home BP in children and adolescents.

SUBJECTS AND METHODS

A total of 778 healthy subjects (358 boys) with mean age 12.3 +/- 3.3 (SD) years (range 6-18 years), height 157 +/- 18 cm (113-198 cm) and weight 50 +/- 18 kg (16-135 kg) were included. Home BP was monitored for 3 days using validated electronic devices (Omron 705IT).

RESULTS

Reliable home BP readings provided by 767 subjects (98%) were analysed. Strong correlations were found between systolic home BP and body height (r = 0.49) and age (r = 0.41), whereas for diastolic BP these correlations were poor (r = 0.11 and 0.08, respectively). The 50th (midpoint of distribution) and the 95th percentile (suggested upper normal limit) for systolic and diastolic home BP in children are provided by body height. There was a marked increase in the estimated 95th percentile for systolic home BP with increasing height in boys (from 119 to 134 mmHg) and less so in girls (from 119 to 128 cm). Regarding diastolic home BP, there was little change with increasing height (from 75 to 80 cm) and no difference between boys and girls.

CONCLUSIONS

These data suggest that home BP monitoring in children and adolescents is feasible. Reference values for home BP in the paediatric population are provided.

Cardiovascular risk prediction based on home blood pressure measurement: The Didima Study

OBJECTIVE

Although home blood pressure (HBP) is being used increasingly in clinical practice, the evidence on its prognostic value is still limited. This study in the general population investigated the value of HBP compared to office measurements (OBP) in predicting cardiovascular risk.

SUBJECTS AND METHODS

In 1997 all adults of the Didima area in Greece were invited to participate in a cross-sectional study involving OBP (two visits) and HBP measurements (3 days). Incident cardiovascular morbidity and cause-specific mortality were assessed after 8.2 +/- 0.2 years (mean +/- SD). Average OBP and HBP were used in Cox regression analysis of fatal and non-fatal cardiovascular events with age, gender, history of cardiovascular disease, use of antihypertensive medication, smoking and diabetes as covariates.

RESULTS

A total of 662 subjects were analysed (mean age at baseline 54.1 +/- 17.6 years). During follow-up 78 deaths (42 cardiovascular) and 67 cardiovascular events (fatal and non-fatal) were documented. Unadjusted hazard ratios for cardiovascular events per 1 mmHg blood pressure increase were for HBP systolic 1.034 (P < 0.001) and diastolic 1.037 (P < 0.01) and for OBP systolic 1.035 (P < 0.001) and diastolic 1.021 (P = 0.07). After adjustment for all available cardiovascular risk predictors, only diastolic OBP remained significant. The addition of HBP in the models already including OBP did not significantly improve the predictive ability. White coat but not masked hypertensives were at high risk.

CONCLUSIONS

This study showed that both HBP and OBP are significant predictors of cardiovascular risk in the general population. However, no prognostic superiority of HBP compared to OBP has been demonstrated.

Practical advice for home blood pressure measurement

Early diagnosis of hypertension is one benefit of home blood pressure monitoring. Home measurement may also be used for the detection of masked hypertension. Home blood pressure readings have a strong correlation with risk, and the method has many advantages over office measurement in the management of hypertension, especially in patients with chronic kidney disease or diabetes. The present article provides practical advice on incorporating home blood pressure monitoring into practice. Patient education and training are discussed, as are tips to aid in the selection of devices for blood pressure measurement at home.

A tool for reliable self-home blood pressure monitoring designed according to the European Society of Hypertension recommendations: the Microlife WatchBP Home monitor

BACKGROUND

Self-blood pressure monitoring by patients at home (HBPM) is being increasingly used in clinical practice and has been endorsed by hypertension societies as an important adjunct to the conventional office blood pressure measurements. Several problems, however, exist regarding the application of HBPM in practice, such as device inaccuracy, observer bias and misreporting, variable monitoring schedule and variable method for summarizing measurements. The European Society of Hypertension Working Group (ESH-WG) on Blood Pressure Monitoring has published detailed recommendations on how to apply HBPM in clinical practice.

OBJECTIVE

The Microlife WatchBP Home monitor is designed to provide reliable and unbiased self-blood pressure monitoring by patients at home, strictly according to the ESH-WG recommendations.

DESIGN

Dual-function automated oscillometric monitor for HBPM in the arm, with memory, PC link capacity and embedded monitoring schedule. The device has a Usual mode for casual HBPM and a Diag (diagnostic) mode for HBPM strictly according to the ESH-WG proposed schedule (duplicate morning and evening measurements for 7 days). Readings are averaged by the device after exclusion of the initial day according to ESH-WG recommendations and can be transferred to PC for storing or printing. A pilot study in hypertensive patients with previous experience in HBPM suggested that the device is user-friendly and well accepted.

CONCLUSION

The Microlife WatchBP Home monitor is a novel device that provides a reliable and unbiased assessment of home blood pressure strictly according to the ESH recommendations.

[Different uses of home blood pressure measurement in the diagnosis and monitoring of hypertension]

OBJECTIVE

To find differences between measurements of clinical blood pressure and self-monitored home blood pressure measurement (HBPM).

DESIGN

Descriptive study developed in a general population census.

SETTING

Primary care.

SUBJECTS

A total of 1411 subjects > or =18 years old were selected by stratified randomized sampling.

METHODS

A skilled nurse made 3 clinical blood pressure (CBP) measurements, and trained patients or their relatives in HBPM, doing 12 in one day. CBP and HBPM employed an electronic device (OMRON 705CP).

RESULTS

A total of 12 HBPM from 1184 subjects (52% women) were completed, with a mean age of 47.6 (SD, 17.2); 195 subjects were known to have hypertension. White-coat effect was diagnosed in 14.9% of subjects with normal pressure, 22.3% of hypertense patients treated and 57.6% of subjects with suspicion of isolated clinical hypertension. Possible isolated clinical hypertension was diagnosed in 10% of subjects without hypertension. White Coat normal pressure was found in 2.3% of untreated subjects and 4.7% of subjects with treated hypertension. 20.7% of subjects with hypertension poorly controlled in the clinic were considered pseudo-refractory (11.4% at the end of dosage interval). 77% of subjects conducted HBPM on their own and 89% thought it easy to do so.

CONCLUSION

Incorporation of HBPM into daily medical practice could avoid 20%-30% of possible mistakes in diagnosis and monitoring of hypertense patients.

[Home blood pressure self-monitoring. Influence of the mean calculation used on the diagnosis of white-coat hypertension]

OBJECTIVE

To describe the variations in the diagnosis performance of home blood pressure self-monitoring (hBPSM) with different methods for mean calculation, in order to diagnose white-coat hypertension (WCH).

DESIGN

Multi-centre, descriptive, and comparative study to assess the diagnosis performance of a test method.

SETTING

Four primary health care centres.

PARTICIPANTS

A total of 157 recently-diagnosed, untreated patients with mild-moderate hypertension took part in the study.

METHODS

The results obtained with hBPSM (3 consecutive days with readings in triplicate, morning-night) were compared with a "gold standard" out-patient blood pressure reading (OutBP).

RESULTS

Systolic and diastolic BP values of the first day and first reading (morning-night) were higher than the remaining days and readings (linear trend P< .001). Results in hBPSM diagnostic performance using all readings to calculate the mean were: sensitivity (S), 47.6%; specificity (Sp), 77.4%; positive and negative predictive values (PPV and NPV), 58.8% and 68.6%, with positive and negative probability coefficients (PPC and NPC), 2.10 and 0.67. When readings with greater patient alarm reaction (first day and first reading, morning-night) were removed, greater values of S (61.9%) were obtained, albeit at expense of an excessive loss in Sp (64.5%) and without improvement in PPC (1.74).

CONCLUSIONS

The diagnostic performance of hBPSM in WCH was low and failed to improve with the use of different systems to calculate mean BP.

Home blood pressure in poorly controlled hypertension: relationship with ambulatory blood pressure and organ damage

OBJECTIVES

(1) To assess whether home blood pressure measurement is a reliable alternative to ambulatory blood pressure monitoring for the evaluation of treated patients with inadequate blood pressure control at the clinic; and (2) to evaluate the relationship between home blood pressure and several target-organ damage markers.

BASIC METHODS

A cross-sectional study was performed in 225 treated hypertensive patients with persistently high blood pressure values at the clinic (systolic blood pressure 140 mmHg and/or diastolic blood pressure 90 mmHg). All study participants underwent clinic blood pressure measurement, 24-h ambulatory blood pressure and home blood pressure monitoring. A subgroup of patients underwent the following procedures: carotid echography (n=74), microalbuminuria determination (n=88) and echocardiography (n=43). We defined out-of-clinic normotension as an average ambulatory or home blood pressure less than 135 mmHg (systolic) and 85 mmHg (diastolic).

MAIN RESULTS

The sensitivity, specificity and positive and negative predictive values of the home blood pressure method for predicting out-of-clinic normotension (with the ambulatory method used as reference), expressed as percentages, were 50, 87, 64 and 79%, respectively. Systolic home blood pressure correlated significantly with left ventricular mass (r=0.33, P<0.05) and microalbuminuria (r=0.24, P<0.05). Similar correlation coefficients were found for systolic ambulatory blood pressure (r=0.32, P<0.05 and r=0.24, P<0.05, respectively). Clinic blood pressure did not correlate with either left ventricular mass or microalbuminuria (r=0.19, P=0.09 and r=0.19, P=0.24, respectively). Diastolic home blood pressure, but not ambulatory blood pressure, correlated negatively with mean carotid intima-media thickness (r=-0.27, P<0.05).

CONCLUSION

Our results suggest that, in patients with poorly controlled hypertension at the clinic, home blood pressure represents a complementary test rather than an alternative to ambulatory blood pressure, and correlates with several target-organ damage markers.

Comparison of agreement between clinic and home-measured blood pressure in the Finnish population: the Finn-HOME Study

BACKGROUND

The purpose of this study was to assess the agreement, mean difference, and the detection and control rates of hypertension, between home and clinic blood pressure (BP) measurement in the Finnish population. Variation in home BP during the measurements was also examined.

METHODS

We studied a representative sample of the adult population (2051 45-74-year-old individuals) in Finland. Subjects included in the study underwent a clinical interview and measurement of clinic and home BP. Thresholds for elevated clinic and home BP were 140/90 and 135/85 mmHg.

RESULTS

The mean difference between home and clinic BP, which increased with BP, was 7.7/3.4 mmHg. Overall agreement in diagnosis was only 75.2% (kappa coefficient 0.50). As compared with home BP, clinic BP overestimated the prevalence of hypertension (48.8 versus 42.5%, P < 0.001) and non-significantly underestimated the control of hypertension (28.7 versus 32.8%, P = 0.11). Evening home BP was 4.1/0.4 mmHg higher than morning BP among untreated subjects, but this difference was non-existent or reversed (0.5/-1.4 mmHg) among treated hypertensive individuals. Home BP decreased with an increasing number of measurements.

CONCLUSIONS

The agreement between home and clinic BP in diagnosing hypertension according to the current guidelines is moderate at best, and the difference between home and clinic BP becomes larger at higher levels of BP. Because of the noticeable differences between these two methods, and the better prognostic accuracy of home BP, we endorse the use of home measurements in clinical practice.

[Appraisal of self-measurement of blood pressure in the diagnosis of isolated clinical hypertension. VAMPAHICA study]

INTRODUCTION

There are no existing studies that appraise cardiovascular morbidity-mortality in patients diagnosed with isolated clinical hypertension (HCA) through self-measurement of blood pressure (AMPA).

OBJECTIVE

To find the prognostic value of AMPA for diagnosing HCA, by means of assessment of cardiovascular morbidity-mortality in clinical and out-patient measurement (MAPA) of blood pressure.

METHOD

Prospective study with 3 cohorts: 1) hypertense patients; 2) patients with HCA, and 3) patients with normal blood pressure. All patients seen at 14 primary care centres with newly diagnosed essential hypertension will be included. AMPA will distinguish who has HCA. One in every four patients will have a MAPA. In parallel, a cohort of people with normal pressure will be selected. The follow-up period will be 3 years. We calculate that the sample needed will be 1400 people. The main measurements will be the prevalence of lesions in the target organ and mortality due to cardiovascular disease in the 3 cohorts. The prevalence of HCA will also be worked out.

DISCUSSION

If the AMPA technique is shown to be as valid as MAPA, then it can be used to diagnose HCA, which would be beneficial because of its accessibility, lower cost and greater comfort for patients.

Automated blood pressure measurement in routine clinical practice

OBJECTIVE

To compare blood pressure measurements taken in routine clinical practice using an automated recorder, the BpTRU (VSM MedTech Ltd, Coquitlam, Canada), with readings taken by a conventional mercury sphygmomanometer.

METHODS

Fifty consecutive patients [28 women, 22 men; mean (+/-SD) age 62+/-16 years] referred to a specialist for management of hypertension had blood pressure taken on the first visit in random order using both a mercury sphygmomanometer and an automated device.

RESULTS

The mean initial automated reading (mmHg) taken with the observer present (162+/-27/85+/-12) was similar to the mean manual blood pressure taken in duplicate (163+/-23/86+12). Both values were higher (P<0.001) than the mean of the next five readings taken with the automated recorder when the patient was resting quietly alone (142+/-21/80+/-12). Women exhibited a greater fall in blood pressure with the automated device than men.

CONCLUSIONS

Use of an automated blood pressure recorder can eliminate some of the white-coat effect associated with readings taken by a mercury sphygmomanometer.

Medición de la presión arterial en el domicilio

Measurement of blood pressure (BP) by the own patient at home has become a popular procedure. Both a great offer of simple electronic devices and publication of multiple studies supporting its usefulness for the diagnosis and control of hypertension have contributed to this fact. In fact, this technique has various advantages over the conventional clinical measurement such as a higher reproducibility, better representation of the usual BP profile of the patient, greater correlation with target organs damage and greater morbimortality predictive value. Besides, there is a potential benefit on the control of patients under antihypertensives and, maybe, a reduction in health expenses at long-term follow-up. Currently, the main hypertension societies recommend the home measurement of BP in some clinical situations. However, it cannot be considered an alternative to the clinical measurement but rather a complementary technique in the evaluation of the hypertensive patient. Here we review the indications and limitations of this procedure in clinical practice.

Reliability of automated blood pressure devices used by hypertensive patients

Automated blood pressure (BP) devices are used by many hypertensive patients in Hong Kong, with or without medical advice. At two community clinics, we invited hypertensive patients aged between 40 and 70 years who used such a device to fill in a questionnaire and to have four sets of BP measurements, automated and mercury, at two visits. Of 290 hypertensive patients 120 fulfilled the criteria, and 73 of these agreed to participate. 53 devices measured arm BP, 21 measured forearm BP. The agreement between the mercury sphygmomanometer and the automated devices was poor, with average differences of 9.5 mmHg for systolic and 9.4 mmHg for diastolic and no clear advantage for either site of measurement. As a means of screening for BP >140/90 mmHg the sensitivity of the automated devices was 81% and the specificity was 80%. There were large variations in how often and under what circumstances the devices had been used. One-fifth of the devices had been acquired on medical advice but only 11% of the participants were aware of the three important conditions for operating such devices. Discussion of automated devices, their role and proper use, should now be part of routine hypertensive care.

[Effectiveness of self-monitoring of blood pressure in white coat hypertension diagnosis. Rationale and design]

OBJECTIVE

To assess the effectiveness of blood pressure self-monitoring at home in front of 24-h blood pressure ambulatory measurement in isolated clinical hypertension diagnosis.

DESIGN

Comparative study of repeated measurements of self-monitoring home BP and 24-h ambulatory BP measurement in a hypertensive patients sample. SETTING AND SUBJECTS TO STUDY: Mild-moderate essential hypertensive patients newly diagnosed or previously diagnosed in which suspect isolated clinical hypertension (BP>140/90 mm Hg in clinical setting repeatedly). It needs a sample of 182 hypertensive patients seen at urban primary health care.

PRINCIPAL MEASUREMENTS

We compute the isolated clinical hypertension prevalence, the sensibility, specificity and positive and negative predictive values, with 95% confidence intervals.

DISCUSSION

Prove the effectiveness of blood pressure self-monitoring at home in insolated clinical hypertension diagnosis, can involve an important cost saving for health care system as in hypertensive patient management (medicines and office visits), as in diagnosis equipment.

Self-measurement of blood pressure at home in the management of hypertension

To be suitable for the management of hypertension, self-measurement of blood pressure (BP) at home should follow international recommendations. The use of accurate and validated measuring devices is an important prerequisite. Upper arm BP monitors are the first choice, while wrist and finger devices cannot be recommended. Measurements should, preferentially, be downloaded from the memory of a device or printed. Reference values have been proposed, but were mostly based on cross-sectional observations and have not yet been widely validated by prospective outcome studies. Currently, levels of home BP of <135 mm Hg systolic and 85 mm Hg diastolic are usually considered normal. Home BP measurement is sometimes recommended as an alternative to ambulatory BP monitoring to diagnose white-coat hypertension.However, home BP measurement cannot replace ambulatory BP monitoring in the diagnosis of hypertension (white-coat), but both techniques have complementary roles. The appropriateness of home BP measurement to guide antihypertensive treatment has only been tested in one large-scale randomized trial: the THOP (Treatment of Hypertension Based on Home or Office Blood Pressure) trial. The THOP trial showed that antihypertensive treatment based on home instead of office BP led to less intensive drug treatment, but also to less BP control with no differences in general wellbeing and left ventricular mass. Home BP monitoring also contributed to the identification of patients with white-coat hypertension. On balance, most evidence supports the view that office BP measurement remains the key in the diagnosis and treatment of hypertension. Treatment can be started without confirmation of elevated office BP in patients with high office BP and target organ damage, or a high cardiovascular risk profile. In patients with raised office BP but without target organ damage (white-coat hypertension), or with normal office BP but unexplained target organ damage (masked hypertension), ambulatory or home BP monitoring or both must be used to confirm the diagnosis. Few longitudinal studies have addressed the long-term prognostic meaning of home BP measurement. Until more prospective data become available, management of hypertension exclusively based on self-measurement of BP at home cannot be recommended.

Diagnostic value of strategy for the detection of white coat hypertension based on ambulatory and home blood pressure monitoring

An algorithm has been proposed for the detection of white coat hypertension among subjects with elevated blood pressure (BP) on at least three clinic visits using home BP monitoring (screening test) and, if this is low, ambulatory BP monitoring (diagnostic test). This study aims to test this strategy in practice. The proposed algorithm was applied in 133 untreated subjects with elevated BP assessed in a previous prospective study using repeated clinic, home and ambulatory BP measurements. The proportions of detected and missed cases of white coat hypertension and the diagnostic value of the algorithm were calculated. By applying the algorithm, 99 subjects (74%) were found eligible for home measurements and 35 (26%) for ambulatory monitoring. There were 38 subjects with white coat hypertension (38%), of whom 15 (39%) were not detected by the proposed strategy. The sensitivity, specificity, and the positive and negative predictive value of the algorithm to diagnose white coat hypertension were 61, 81, 66 and 77%, respectively. Of the 34 subjects with normal BP on the third clinic visit, 15 (42%) had elevated home and/or ambulatory BP. These data suggest that, using the proposed strategy, many white coat hypertensives may remain undetected and may receive unnecessary long-term drug treatment. Therefore, more research is needed on the optimal strategy for detecting white coat hypertension in clinical practice.

Relationship between ambulatory blood pressure and follow-up clinic blood pressure in elderly patients with systolic hypertension

BACKGROUND

Patients with elevated clinic blood pressure and normal ambulatory blood pressure have a better prognosis than patients with sustained ambulatory hypertension, and may not have to be treated with antihypertensive drugs. On the contrary, current guidelines emphasize repeated clinic blood pressure measurements for the initiation of antihypertensive therapy.

OBJECTIVE

To examine the relationship between ambulatory blood pressure at baseline and clinic blood pressure after 6 months of follow-up in untreated hypertensive patients, and the relationships of these pressures with the subsequent incidence of cardiovascular events.

METHODS

Patients who were > or = 60 years old, with systolic clinic blood pressure of 160-219 mmHg and diastolic pressure < 95 mmHg, participated in the Systolic Hypertension in Europe trial. The relationship between ambulatory blood pressure at baseline and clinic blood pressure after 6 months of follow-up was examined in 295 patients enrolled in the Ambulatory Blood Pressure Monitoring substudy and randomized to the placebo arm, and who were still on double-blind treatment and not taking other antihypertensive drugs after 6 months follow-up.

RESULTS

Age averaged 70 +/- 6 years, 41% were men, and baseline daytime ambulatory blood pressure was 152 +/- 16/84 +/- 10 mmHg; clinic blood pressure decreased from 173 +/- 10/86 +/- 6 mmHg at baseline to 163 +/- 20/85 +/- 9 mmHg at month 6. Systolic daytime ambulatory blood pressure at baseline and systolic clinic blood pressure at month 6 were considered normal if < 140 mmHg. Of the 74 patients with normal systolic daytime ambulatory blood pressure at baseline, only seven (9.5%) had a normal systolic clinic blood pressure during follow-up. Conversely, of the 24 patients with normal follow-up clinic blood pressure, only seven (29%) had a normal systolic daytime ambulatory blood pressure at baseline. The incidence of cardiovascular events beyond the 6-month visit was significantly related to baseline ambulatory blood pressure but not to follow-up clinic pressure.

CONCLUSIONS

Baseline daytime ambulatory blood pressure and follow-up clinic blood pressure do not identify the same patients for antihypertensive treatment. Baseline ambulatory pressure is a better predictor of cardiovascular events than follow-up clinic pressure.

Tele-monitoring of home blood pressure in treated hypertensive patients

AIM

To compare the accuracy of clinic blood pressure (CBP) and telemedical home blood pressure (HBP) measurement in the assessment of antihypertensive effect.

METHODS

362 patients on antihypertensive medication performed HBP measurement (5 days, duplicate measurements, four times daily) and ambulatory blood pressure (ABP) monitoring in random order. Main outcome measure was the agreement of CBP and HBP with daytime ABP.

RESULTS

CBP was much higher than ABP and average HBP (p < 0.001). There was a progressive decline in HBP over the course of the study, achieving the level of daytime ABP on the last 2 monitoring days. The correlation between CBP and ABP was weak (systolic: r = 0.343, diastolic r = 0.430), whereas strong correlations existed between HBP and ABP (systolic r = 0.804, diastolic r = 0.776). A progressive improvement in the strength of the correlation between average HBP of single days and ABP was obtained over the 5 monitoring days. The HBP readings taken in the afternoon showed a stronger correlation with ABP than the values measured in the morning, at noon and in the evening. Averaging more HBP readings taken on succeeding days resulted in a progressive improvement in the agreement with ABP with a further benefit when readings of day 1 were included.

CONCLUSIONS

The accuracy of telemedical HBP measurement is substantially better than that of CBP. The results suggest, that HBP should be measured for 5 days, and afternoon measurements should be preferred in assessing control of hypertension.

Home or self blood pressure measurement? What is the correct term?

OBJECTIVE

Blood pressure measurements taken by patients at home (HBP) are usually referred to as 'self' or 'home' measurements. To demonstrate the most appropriate term we compared self-home measurements (S-HBP), with home measurements taken by relatives (R-HBP), clinic measurements taken by physicians (P-CBP) and self-measurements in the clinic (S-CBP).

PATIENTS AND METHODS

Thirty treated hypertensives were randomized to an initial clinic BP (CBP) monitoring period (week 1, P-CBP followed by S-CBP measurements, or the opposite; 1 visit each), then to a HBP monitoring period (weeks 2-3, S-HBP followed by R-HBP or the opposite; 3 workdays each), and finally to a second CBP monitoring period (week 4, S-CBP followed by P-CBP, or the opposite). Triplicate morning trough measurements were taken per occasion using the same fully automated device.

RESULTS

There was no difference between S-CBP and P-CBP (mean difference -1.9 +/- 6.1 mmHg, 95% confidence interval (CI) -4.2, 0.4/-1.6 +/- 4.7, 95% CI -3.3, 0.2, systolic/diastolic), or between S-HBP and R-HBP (-0.9 +/- 6.9, 95% CI -3.5, 1.8/-0.4 +/- 4.3, 95% CI -2.0, 1.2). S-CBP was higher than S-HBP (mean difference 9.3 +/- 9.0/4.9 +/- 5.4 mmHg, systolic/diastolic, P < 0.001) and R-HBP (8.4 +/- 9.1/4.5 +/- 5.0, P < 0.001). P-CBP was also higher than S-HBP (11.2 +/- 11.9/6.5 +/- 6.8, P < 0.001) and R-HBP (10.3 +/- 11.2/6.1 +/- 6.5, P < 0.001).

CONCLUSIONS

Self-measurements provide similar BP levels to measurements taken by relatives or physicians, provided that measurements are taken in the same setting. 'Self-BP' is a misnomer because self-measurement has no impact on the difference between home and clinic BP. Given that this difference can be exclusively attributed to the effect of the different setting, the term 'home BP' represents a more appropriate term.

Accuracy of telemedical home blood pressure measurement in the diagnosis of hypertension

This study was conducted to compare the accuracy of clinic blood pressure (CBP) and telemedical home blood pressure (HBP) measurement in the diagnosis of hypertension in primary care. The study subjects were 411 patients with average CBP > or =140 mmHg systolic or > or =90 mmHg diastolic, who performed telemedical HBP measurement (5 days, four times daily) and ambulatory blood pressure (ABP) monitoring in random order. Main outcome measure was the agreement of CBP and HBP with daytime ABP. CBP was much higher than daytime ABP and average HBP (P<0.001) with no difference between the latter two. The correlation between CBP and ABP was weak (systolic: r=0.499, diastolic: r=0.543), whereas strong correlations existed between HBP and ABP (systolic: r=0.847, diastolic: r=0.812). A progressive improvement in the strength of the linear regression between average HBP of single days and ABP was obtained from day 1 to day 4, with no further benefit obtained on the fifth day. The HBP readings taken at noon and in the afternoon showed significantly stronger correlations with ABP than the blood pressures measured in the morning and in the evening. In conclusion, the accuracy of telemedical HBP measurement was substantially better than that of CBP in the diagnosis of hypertension in primary care. HBP most accurately reflected ABP on the fourth day of monitoring, and the readings at noon and in the afternoon seemed to be most accurate.

Which is the correct term for blood pressure measurements taken at home?

The terms 'self-blood pressure' and 'home blood pressure' are being used to describe measurements of blood pressure taken by the patients at home. However, home measurements are not always self-measurements, because these are often taken by the patients' relatives. There is little evidence on the effect of self-measurement on the level of blood pressure taken using automated electronic devices. In regard to clinic blood pressure, two studies using automated devices found no difference between measurements taken by physicians or patients themselves, irrespective of whether self-measurements were taken in the presence or the absence of the physician. In regard to home blood pressure, one randomized crossover trial showed no difference between home measurements taken by the patients themselves or their relatives using fully automated devices. On the other hand, many studies have consistently shown home blood pressure to be lower than clinic pressure. Taken together these data suggest that self-measurement has no effect on the level of blood pressure, either in the clinic, or at home. The lower level of home in comparison to clinic blood pressure seems to be exclusively attributed to the effect of the different setting, rather than the person who is taking measurements. Therefore the term 'self blood pressure' seems to be a misnomer, whereas the term 'home blood pressure' represents a more appropriate term for home measurements taken by patients or their relatives.

Loaned self-measurement equipment model compared with ambulatory blood pressure monitoring

OBJECTIVE

To compare the correspondence between the loaned self-measurement equipment model (LSEM), 24 h awake ambulatory blood pressure monitoring (ABPM) and clinic blood pressure (CBP).

DESIGN

A cross-sectional study was carried out involving 90 hypertensive and normotensive subjects.

METHODS

We used a variation of home measurement, the loaned self-measurement equipment model (LSEM), that consisted of lending a number of sphygmomanometers, the property of the clinic, to patients for 3-day periods. The correspondence of results from LSEM was measured against the difference between the two averages, the correlation coefficients and the average unweighted absolute differences.

RESULTS

The average difference between CBP and ABPM was 6.1/2.5 mmHg (P<0.001, r =0.54/0.63). Between CBP and LSEM, it was 6.6/1.4 mmHg (P<0.001/ 0.08, r =0.52/0.63), and between the ABPM and LSEM 0.5/-1.0 mmHg (P=0.70/0.14, r =0.71/0.75). The average unweighted absolute differences between LSEM and ABPM readings were 5.5 and 1.5 mmHg for systolic and diastolic blood pressure, respectively, whereas the average difference between CBP and ABPM means was much higher, at 6.8 mmHg for systolic and 2.7 mmHg for diastolic pressure. Agreement in the diagnosis of systolic hypertension between LSEM and ABPM was found in 78.8% of the individuals, and of diastolic hypertension in 76.7%.

CONCLUSION

Blood pressure readings taken using LSEM have a better correspondence than CBP in predicting the awake ABPM value, although the disagreement in terms of diagnosing hypertension should be noted.

Self-measured versus ambulatory blood pressure in the diagnosis of hypertension

OBJECTIVE

We examined to what extent self-measurement of blood pressure at home (HBP) can be an alternative to ambulatory monitoring (ABP) to diagnose white-coat hypertension.

METHODS

In 247 untreated patients, we compared the white-coat effects obtained by HBP and ABP. The thresholds to diagnose hypertension were > or = 140/> or = 90 mmHg for conventional blood pressure (CBP) and > or = 135/> or = 85 mmHg for daytime ABP and HBP.

RESULTS

Mean systolic/diastolic CBP, HBP and ABP were 155.4/100.0, 143.1/91.5 and 148.1/95.0 mmHg, respectively. The white-coat effect was 5.0/3.5 mmHg larger on HBP compared with ABP (12.3/8.6 versus 7.2/5.0 mmHg; P < 0.001). The correlation coefficients between the white-coat effects based on HBP and ABP were 0.74 systolic and 0.60 diastolic (P < 0.001). With ABP as a reference, the specificity of HBP to detect white-coat hypertension was 88.6%, and the sensitivity was 68.4%.

CONCLUSION

Our findings are in line with the recommendations of the ASH Ad Hoc Panel that recommends HBP for screening while ABP has a better prognostic accuracy.

Clinic, home and ambulatory pulse pressure: comparison and reproducibility

OBJECTIVE

Recent evidence suggests that pulse pressure (PP) is an independent predictor of cardiovascular risk. The objective of this study was to compare mean values and reproducibility of PP obtained in the clinic (CPP), at home (HPP) and with ambulatory monitoring (APP) and to evaluate potential implications for trials aiming to assess drug effects on PP.

METHODS

A total of 393 hypertensive subjects [mean age 51.5 +/- 11.5 (SD) years, 59% men, 35% treated] measured CPP (two visits), HPP (6 days) and APP (24 h). The reproducibility of PP was assessed using the SD of differences (SDD) between measurements in 133 untreated subjects who had repeated CPP (five visits), HPP (6 days) and APP measurements (two occasions).

RESULTS

There was no difference between mean CPP (51.0 +/- 13.3 mmHg) and HPP (50.2 +/- 11.0) whereas APP (48.8 +/- 8.4) was lower than both CPP [mean difference 2.3 +/- 10.3 mmHg; 95% confidence interval (CI), 1.2, 3.3; P < 0.01] and HPP (1.5 +/- 7.8; 95% CI, 0.7, 2.3; P < 0.01). The SDD between repeated measurements was about 10 mmHg for CPP (one visit), 5.2 mmHg for HPP (2 days) and 4 mmHg for APP (24-h). For a parallel comparative trial aiming to detect a difference of 3 mmHg PP in the effect of two drugs, 415 subjects would be required when using CPP, compared to 127 using HPP and 63 using APP.

CONCLUSIONS

These data suggest that although differences among mean values of CPP, HPP and APP are small, differences in their reproducibility are important and should be taken into account in the design of trials assessing drug effects on PP.

Quality control of the blood pressure phenotype in the European Project on Genes in Hypertension

OBJECTIVES

In the European Project on Genes in Hypertension (EPOGH) standardized epidemiological methods were used to determine complex phenotypes consisting of blood pressure (BP) in combination with other traits. In this report, we present the quality control of one of the BP phenotypes.

METHODS

In seven European countries eight different research groups recruited random samples of nuclear families. Trained observers measured the BP five times consecutively with the participants in the seated position at each of two separate home visits, 1 to 3 weeks apart, according to the guidelines of the British Hypertension Society. Quality assurance and quality control of this BP phenotype were implemented according to detailed instructions defined in the protocol of the EPOGH study.

RESULTS

On 31 August 2001, BP measurements of 2476 subjects were available for analysis. Fewer BP readings than the five planned per visit occurred in one of the eight centres, but only in 0.4% of the home visits. Across centres the relative frequency of identical consecutive readings for systolic or diastolic blood pressure varied from 0 to 6%. The occurrence of odd readings ranged from 0 to 0.1%. Of the 49,488 systolic and diastolic BP readings, 24.0% ended on a zero (expected 20%). In most EPOGH centres there was a progressive decline in the BP from the first to the second home visit. Overall, these decreases averaged 2.36 mmHg [95% confidence interval (CI): 1.98-2.74, P < 0.001] for systolic BP and 1.74 mmHg (95% CI: 1.46-2.02, P < 0.001) for diastolic BP.

CONCLUSIONS

Quality assurance and control should be planned at the design stage of a project involving BP measurement and implemented from its very beginnings until the end. The procedures of quality assurance set up in the EPOGH study for the BP measurements resulted in a well-defined BP phenotype, which was consistent across centres.

Blood pressure control assessed by home, ambulatory and conventional blood pressure measurements in the Japanese general population: the Ohasama study

To assess blood pressure control in the Japanese population, we analyzed previously obtained measurements of conventional, home and ambulatory blood pressures in 1,174 subjects aged > or =40 in a Japanese community. On the basis of conventional blood pressure values and the use of antihypertensive medication, participants were classified as normotensive, untreated hypertensive and treated hypertensive subjects. When 140/90, 135/85 and 135/85 mmHg were used as the hypertension criteria for conventional, home and ambulatory blood pressure measurements, respectively, all three blood pressure values were higher in untreated and treated hypertensive subjects than in normotensive subjects. Among the treated hypertensive subjects, approximately half were classified as hypertensive not only by conventional blood pressure, but also by home or ambulatory measurements. Approximately 10% of the subjects defined as normotensive by conventional blood pressure measurement were classified as hypertensive by home or ambulatory measurements, whereas 60% of the untreated hypertensive subjects as defined by conventional blood pressure measurement had normal home or ambulatory blood pressure values. Therefore, we concluded that 1) the poor blood pressure control in treated hypertensive subjects was attributable not only to the white coat effect but also to inadequate control of blood pressure; and 2) a certain percentage of subjects were misclassified as hypertensive or normotensive by conventional blood pressure measurement.

Reproducibility and cost of blood pressure self-measurement using the 'Loaned Self-measurement Equipment Model'

OBJECTIVE

To determine the reproducibility and the cost of the Loaned Self-measurement Equipment Model for blood pressure.

SUBJECTS

Seventy-five subjects with non-complicated essential hypertension, having an average age of 56.2 +/- 11 years, were evaluated.

METHODS

The Loaned Self-measurement Equipment Model consists of a set of sphygmomanometers belonging to the clinic, loaned to patients for 3-day periods for them to carry out 27 readings, and then returned. Using a mercury sphygmomanometer, a nurse carried out office blood pressure readings during two visits. A month later, the same procedure was repeated under the same clinical conditions. The agreement between studies was assessed by correlation coefficients, coefficients of variation and standard deviation of the differences (SDD).

RESULTS

The office blood pressure was 147 +/- 17/89 +/- 12 mmHg during visit A, and 145 +/- 16/88 +/- 11 mmHg during visit B. The self-measurement blood pressure was 139 +/- 16/84 +/- 10 mmHg during the first visit, and 136 +/- 15/84 +/- 11 mmHg during the second visit. In neither of the cases were the differences statistically significant. The correlation coefficients for the office and self-measurement systolic blood pressure were statistically significant (P = 0.018), while those for the diastolic blood pressure were not statistically significant. The SDD for self-measurement systolic blood pressure was 10.7, compared to 15.0 for the office blood pressure (P < 0.01). The comparison in the case of diastolic blood pressure was not significant. The cost of each loan was $5.85 (US dollars).

CONCLUSIONS

The Loaned Self-measurement Equipment Model has a good short-term reproducibility, and the cost is reasonable.