Benefits of ambulatory blood pressure monitoring in the design of antihypertensive drug trials

REVIEW IN DEPTH: Ambulatory blood pressure monitoring (ABPM) offers substantial advantages over conventional clinic measurement in the assessment of antihypertensive agents. There is a greater reproducibility of an average blood pressure taken from multiple readings,s and in the setting of a clinical trial this translates into increased precision of the assessment of mean antihypertensive effect. The temporal profile of blood pressure and the antihypertensive effect of an agent can be studied directly, and times of the day of particular clinical importance, such as the end of the dosing period and the early morning period, can be studied more easily than for conventional blood pressure measurement. ABPM reduces the size of any placebo effect on blood pressure to very low values, and it can be used to exclude white-coat hypertensives from clinical trials, thereby reducing the noise in a clinical trial. The role of ABPM in drug evaluation looks set to increase further with new developments in blood pressure measurement technology.     

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.     

动态血压监测与高血压病预后的关系

目的 :探讨动态血压 (ABP)及偶测血压 (CBP)与高血压预后的关系。方法 :2 2 0例原发性高血压患者入选时分别测量基础状态下ABP及CBP、并根据白昼舒张压水平分为高、中、低 3个亚组 (HL、ML、LL) ,然后长期随访观察与高血压病相关的心脑血管“事件”。结果 :平均随访 38个月 ,发生各类“事件”者 2 6例 ,单因素分析表明 :“事件”组各项ABP参数明显高于“非事件”组 (P <0 0 5～ 0 0 1) ,而 2组CBP间无显著差异 (P >0 0 5 )。LL、ML、HL 3个亚组中“事件”发生率分别为 2例 10 0人年、3 4例 10 0人年及 6 3例 10 0人年。多因素分析显示 :SBP节律、夜间SBP水平及总胆固醇 (CT)水平为高血压患者“事件”发生的独立危险因素 ,分别为RR =3 0 8、RR =1.2 6、RR =1.4 9(P <0 0 5～ 0 0 1)。结论 :ABP在判断高血压预后方面较CBP更具有临床意义 ,较高的ABP水平提示不良的预后 ,SBP节律、夜间SBP水平是预测高血压患者心脑血管“事件”及肾脏受损的独立危险因素     

Arterial distensibility and ambulatory blood pressure monitoring in essential hypertension

Arterial distensibility estimated by carotid femoral pulse wave velocity was evaluated in 22 patients with sustained essential hypertension, together with 3 different methods of blood pressure (BP) measurement: mercury sphygmomanometer, semiautomatic BP recording using the Dinamap apparatus and 24-hour ambulatory BP monitoring using a Spacelabs monitor. Although pulse wave velocity did not correlate with BP measured by mercury sphygmomanometer, it strongly and positively correlated with BP measurements using the other 2 procedures. The best correlation was observed with ambulatory BP with respect to systolic BP only (r = 0.685, p less than 0.001). Since cardiovascular morbidity and mortality in hypertensive patients is mainly related to lesions of the large arteries, the determination of pulse wave velocity together with ambulatory BP measurements is proposed for the evaluation of cardiovascular risk.     

Diagnosis of white coat hypertension by ambulatory blood pressure monitoring.

White coat hypertension (WCH) is common in referred hypertensive patients. Ambulatory blood pressure monitoring (ABPM) is not free from the white coat syndrome. We examined the use of the elevation of the first and last measurements of ABPM for diagnosis of WCH in a hypertensive population that had been referred to a hospital-based hypertension unit. Data were obtained on 1350 patients for clinic and ABPM parameters. WCH, as diagnosed by conventional clinic blood pressure (BP) measurement, was compared with a variety of alternative methods determined from ABPM. In all cases, mean daytime pressure was <135 mm Hg/85 mm Hg with an elevation of clinic BP >/=140 mm Hg systolic or 90 mm Hg diastolic. The definitions tested for this elevation were first hour mean pressure, first reading, maximum reading in first hour, last hour mean pressure, last reading, maximum reading in the last hour and maximum reading in first or last hour. Elevation of the maximum pressure in the first hour or last hour above 140 mm Hg systolic or 90 mm Hg diastolic showed a high level of agreement (kappa=0.91) with classical WCH for diagnosis of the white coat syndrome. Termed ambulatory white coat hypertension, patients with this finding were older than classic white coat patients and had higher daytime (127+/-6/78+/-5 mm Hg versus 121+/-5.5/74+/-6 mm Hg, P<0.005 for systolic and diastolic) and nighttime (114+/-11/67+/-8 mm Hg versus 106+/-9/61+/-6 mm Hg, P<0.005 for systolic and diastolic) pressures. They also had a significantly greater Sokolow-Lyon index (leads V(1)+V(5), 21+/-7 mV versus 18+/-6 mV). Elevation of BP above 140 mm Hg systolic or 90 mm Hg diastolic in the first or last hour of monitoring diagnoses patients with a white coat response in whom there is a higher BP profile than in patients with classic white coat response alone. We suggest, therefore, that this is a better measure of the white coat phenomenon.     

Cost-effectiveness of ambulatory blood pressure monitoring in the follow-up of hypertension

Aims. To study the cost of the follow-up of hypertension in primary care (PC) using clinical blood pressure (CBP) and ambulatory blood pressure monitoring (ABPM), and to analyse the cost-effectiveness (CE) of both methods. Major findings and principal conclusion. Good control of hypertension was achieved in 8.3% with CBP (95% CI 4.8-11.8) and in 55.6% with ABPM (95% CI 49.3-61.9). The cost of one patient with good control of hypertension is almost four times higher with CBP than with ABPM (€940 vs €238). Reaching the gold standard (ABPM) involved an after-cost of €115 per patient. The results for a 5% discount rate showed a saving of €68,883 if ABPM was performed in all the patients included in the study (n = 241, €285 per patient). An analysis of sensitivity, changing the discount rate and life expectancy indicated that ABPM provides a better CE ratio and a lower global cost. ABPM is more cost-effective than CBP. However, if we include the new treatment cost of poorly monitored patients, it is less cost-effective. Excellent control of hypertension is still an important challenge for all healthcare professionals, especially for those working in PC, where most monitoring of hypertensive patients takes place.     

氯沙坦的降压疗效及其对血压谷/峰比值的影响

目的:以动态血压观察氯沙坦片对原发性高血压病患者的疗效及其对血压谷峰比值的影响。方法:60例原发性高血压病患者被随机均分为氯沙坦片组和苯那普利片组(各30例),分别给予氯沙坦片50～100mg和苯那普利片10～20mg,晨服,1次/日,疗程16周。结果:治疗后两组病人的血压均有明显下降,氯沙坦片组,收缩压(SBP)由治疗前的168.2±16.3 mmHg降至138.3±17.2mmHg,舒张压(DBP)由治疗前的99.8±8.1mmHg降至治疗后的85.3±6.4mmHg,SBP、DBP谷/峰比值分别为0.73和0.68;苯那普利组;SBP由治疗前的169.4±16.7mmHg降至139.3±16mmHg,DBP由治疗前的98.7±9.2mmHg降至治疗后的84.6±6.3mmHg,SBP、DBP谷/峰比值分别为0.67、0.63,与治疗前比较,P均<0.01,但组间比较差异不显著(P>0.05)。氯沙坦组无明显副作用,苯那普利组有6例出现咳嗽,2例咳嗽较剧烈,退出观察。结论:氯沙坦片能安全、有效、平稳地降低高血压病人的血压,其疗效与苯那普利疗效相似,但副作用明显少于后者,是高血压治疗的理想用药。     

Transcranial doppler sonography and ambulatory blood pressure monitoring in patients with hypertension.

To appraise the value of transcranial Doppler sonography (TCD) for assessment of hypertensive cerebrovascular damage, the relationship between ambulatory blood pressure (BP) and indices of cerebral circulation determined by TCD was investigated. Subjects were 55 inpatients with or without hypertension, including 13 patients with histories of cerebrovascular attacks. Mean flow velocity (MFV) in the middle cerebral artery was measured by TCD, then the cerebrovascular resistance index (CVRI; mean BP/MFV) and the Fourier PI1 (pulsatility index of the first Fourier harmonic of the flow-velocity waveform) were determined as indices of cerebrovascular resistance. CO2 reactivity of MFV was estimated as an index of cerebrovascular flow reserve. CVRI positively correlated with both daytime and nighttime BP as well as with age (p<0.01). Fourier PI1 positively correlated with nighttime BP and age (p<0.01). CO2 reactivity did not correlate with any of the ambulatory BP parameters, but negatively correlated with age (p<0.01). LV mass index significantly correlated with ambulatory BP parameters, CVRI, and Fourier PI1 but did not correlate with CO2 reactivity. Multiple regression analyses showed that nighttime systolic BP was a significant correlate for CVRI and Fourier PI1, but not for CO2 reactivity, and that history of cerebrovascular attack was significant for CVRI and CO2 reactivity. We conclude that cerebrovascular resistance determined by TCD accords with the results of ambulatory BP and LVMI, and thus could be successfully used to detect the early stage of hypertensive cerebrovascular change. Cerebrovascular flow reserve would be relatively preserved in hypertensive patients without cerebrovascular diseases.     

Canadian hypertension society guidelines for ambulatory blood pressure monitoring

The Canadian Hypertension Society has developed guidelines for the use of ambulatory blood pressure (BP) monitoring in clinical practice. Published articles with the best available levels of evidence were used to support the following recommendations:Physicians should only use ambulatory BP monitoring devices that have been validated independently using established protocols.A decision to withhold drug therapy based upon the ambulatory BP should take into account normal values for 24-h and awake ambulatory BP.Based upon studies on prognosis and a clinical trial based upon BP control as an outcome, ambulatory BP monitoring should be considered for untreated patients whenever an office-induced increase in BP is suspected.Ambulatory BP monitoring should be considered for treated patients suspected of having an office-induced increase in BP, including individuals with apparent resistance to drug therapy, symptoms suggestive of hypotension, and fluctuating office BP readings.Based upon studies on prognosis, changes in nocturnal BP should be taken into account in any decision to withhold drug therapy based upon the ambulatory BP.Further studies are required to determine whether the clinical benefit of antihypertensive therapy is more closely related to ambulatory or office BP.     

Experience with 24-hour ambulatory blood pressure monitoring in hypertension

Traditional sphygmomanometric blood pressure measurements may lead to errors in the diagnosis of arterial hypertension due to a number of factors, among which are the alerting reaction and pressor response induced in patients by the doctor's visit. This phenomenon, as quantified in our laboratory by continuous intraarterial recordings, is responsible for an average rise in systolic and diastolic blood pressure of 27/15 mm Hg, a rise that does not seem to be reduced by simply desensitizing the patient by means of more frequent physician visits. Twenty-four hour ambulatory blood pressure monitoring may theoretically improve the diagnostic approach to hypertensive patients by overcoming some limitations of isolated cuff measurements. In recording intraarterial blood pressure in 108 ambulant hypertensive subjects, we have found that 24-hour blood pressure values are able to discriminate among patients with different degrees of target organ damage better than isolated sphygmomanometric readings. Moreover, these studies have indicated that 24-hour blood pressure variability may be as important as blood pressure mean values in the assessment of cardiovascular complications. In clinical practice, however, intraarterial blood pressure monitoring is not feasible, and only noninvasive recorders can be used. Use of these devices does not induce any alerting reaction in the patients and does not interfere with day-night blood pressure changes. Although it is characterized by intermittent readings, this approach is not incompatible with a precise estimate of 24-hour blood pressure mean values.(ABSTRACT TRUNCATED AT 250 WORDS)     

Impact of ambulatory blood pressure monitoring on the management of hypertension in children

BACKGROUND: Ambulatory blood pressure monitoring (ABPM) is widely utilized for the evaluation and management of hypertension in adults but has not been routinely used in the care of hypertensive children. DESIGN: To examine the potential impact that the routine use of ABPM might have on the evaluation and management of hypertension in children, we reviewed our early experience with this technique, comparing management decisions based on ABPM with those based on casual blood pressure readings. METHODS: Twenty children (4-17 years old) underwent ABPM for either the initial evaluation of suspected hypertension or the ongoing management of known hypertension. ABPM studies were considered abnormal if over 40% of both systolic and/or diastolic blood pressure readings were above the 95th percentile for the child's age and gender. RESULTS: Of 13 children studied for suspected hypertension, nine had abnormal ABPM studies and were treated, but four had normal results and were therefore not treated. Of seven children with known hypertension studied by ABPM to assess their blood pressure control further, three had normal results and no management changes were made, but four had abnormal studies, prompting a change in therapy or further diagnostic testing. Overall, eight out of 20 ABPM studies led to the initiation of further diagnostic evaluation or a change in planned or ongoing therapy. CONCLUSIONS: We conclude that ABPM has the potential to become an important tool in the evaluation and management of childhood hypertension, and suggest that more widespread use of this technique in children is appropriate.     

老年高血压病及脑卒中患者动态血压分析的探讨

目的　探讨老年高血压病及脑卒中患者动态血压的特点。方法　对 30 7例高血压病患者进行动态血压监测 ,并根据年龄分为 :A组 (对照组n =16 1) ,年龄 <6 0岁 ;B组 (观察组n =14 6 ) ,年龄≥ 6 0岁。两组中又根据是否合并脑卒中 ,进一步分为 4个亚组A1 、B1 组 (无脑卒中 ) ,A2 、B2 组 (脑卒中 )。结果　B组老年高血压患者无论有无脑卒中 ,其血压昼夜节律性明显低于A组 (P <0 .0 5 )。B组脉压 [B1 组昼脉压 5 2 .9mmHg(1mmHg =0 .133kPa) ,夜脉压4 9.4mmHg;B2 组昼脉压 5 3.2mmHg ,夜脉压 5 3mmHg]较A组脉压 (A1 组昼脉压 4 3.6mmHg ,夜脉压 4 0 .3mmHg ;A2组昼脉压 4 7.2mmHg ,夜脉压 4 4mmHg)明显增大 (P <0 .0 5 )。B2 组夜间收缩压 (12 8.1mmHg)明显高于其余 3组 (A1组 117.4mmHg、A2 组 12 1.1mmHg、B1 组 12 0 .7mmHg ,P <0 .0 5 )。结论　血压昼夜节律降低、动态脉压增大及夜间收缩压增高是老年高血压患者动态血压的特点     

Verapamil and 24-hour ambulatory blood pressure monitoring in essential hypertension

The antihypertensive effects of oral regular and slow-release verapamil, a calcium-channel blocking agent, were evaluated in 22 patients with mild to moderate hypertension (sitting diastolic blood pressure [DBP] 95 to 112 mm Hg). The dose required to control blood pressure varied from 80 to 120 mg, 3 times a day. All patients received regular verapamil for a further 3 to 4 months, when systolic blood pressure (SBP) and DBP had risen from the end of the open-label phase. During a double-blind phase patients were randomly assigned to continue the same dose of regular verapamil, 3 times a day, or an equivalent daily dose of sustained-release verapamil (240 to 360 mg once a day). Seven of the 11 patients on regular and 3 of the 11 on sustained-release verapamil were also taking diuretics. This antihypertensive program was continued for at least 4 weeks. During the efficacy period, 24-hour ambulatory blood pressure monitoring was carried out. Mean 24-hour SBP and DBP were 133 +/- 20 and 89 +/- 13 mm Hg, respectively, on regular and 131 +/- 22 and 87 +/- 12 mm Hg, respectively, on sustained-release verapamil. There were no statistically significant differences noted between the 2 groups. Mean SBP and DBP varied similarly during awake and sleep hours with both formulations of verapamil. With regular verapamil, SBP was 139 +/- 18 and 124 +/- 20 mm Hg and DBP 92 +/- 11 and 84 +/- 13 mm Hg during awake and sleep hours, respectively; with sustained release, SBP was 138 +/- 21 and 122 +/- 22 mm Hg and DBP 92 +/- 10 and 80 +/- 10 mm Hg during awake and sleep hours, respectively. Heart rate fell during the entry period and continued during the entire study period. No other adverse effects were noted during the double-blind phase. In summary, verapamil is an effective antihypertensive medication and can be administered once a day as a sustained-release preparation; it is most useful in patients in whom adrenergic blocking drugs are indicated.     

动态血压监测指导依那普利抗原发性高血压治疗临床观察

目的根据原发性高血压患者24h血压变化规律决定依那普利给药时间,观察降压疗效。方法对于临床确诊的1~2级原发性高血压患者,服用安慰剂2周后,根据24h动态血压监测夜间血压与白昼相比是否下降≥10%或10mmHg,分为勺型高血压及非勺型高血压,对勺型高血压者6:00及下午血压最高值前3h分别给予依那普利5mg,非勺型者6:00及18:00分别给予依那普利5mg,2周后,若患者坐位舒张压≥90mmHg,依那普利加量至10mg,每日2次。8周后复查24h动态血压。结果完成研究的80例原发性高血压患者中勺型58例,占72.5%,非勺型22例,占27.5%。依那普利对勺型组和非勺型组患者有效率分别为(52/58)89.7%,(19/22)86.4%,勺型组24h平均血压、白昼(6:00~22:00)血压、夜间(22:00~6:00)血压分别下降9.9/6.6mmHg,9.0/6.8mmHg,2.8/2.6mmHg,非勺型组分别下降13.9/7.6mmHg,11.9/6.6mmHg,13.8/10.4mmHg。两组白昼及夜间血压负荷均显著下降。勺型组收缩压与舒张压谷峰比值分别为66.6%,63.5%,非勺型组70.6%,66.5%。结论在时间治疗学理论指导下,依那普利每日给药两次能24h平稳降压,是一种价廉物美的降压药物,值得推广应用。     

Twenty-four hour ambulatory blood pressure monitoring pattern of resistant hypertension

OBJECTIVE: Ambulatory blood pressure monitoring (ABPM) is a tool to diagnose resistant hypertension (RH). The objective of this study is to describe the pattern of 24-h ABPM in patients using at least three anti hypertensive drugs without blood pressure (BP) control, classifying them as true RH or white-coat RH. METHODS: A cross-sectional study involving resistant hypertensives that were submitted to clinical, laboratory and 2D-echocardiographic evaluation. Ambulatory blood pressure monitoring was used to diagnose true or white-coat RH. The chi-squared test was used for comparisons among categorical variables and Kruskall-Wallis test for continuous ones. RESULTS: Of the 286 patients, 161 (56.3%) were classified as true RH and 125 (43.7%) as white-coat RH. Sex, age, office BP and the cardiovascular risk factors for both groups were similar. True resistant hypertensives had more target organ damage then white-coat resistant hypertensives; nephropathy (40.1 versus 23.9%, P=0.007) and left ventricular hypertrophy (83.3 versus 76.3%, P=0.05). In ABPM, the true RH group had a smaller nocturnal systolic and diastolic BP reduction (6.4+/-8.8 versus 9.8+/-7.5 mmHg, P=0.0004; 10.4+/-9.6 versus 13.6+/-9.2 mmHg, P=0.001) and 68.7% of them were non-dippers versus 49.6% in the white-coat RH group (P=0.001). True RH also had a larger 24 h pulse pressure (65.8+/-13.7 versus 51.5+/-10.0 mmHg, P < 0.0001). CONCLUSIONS: Ambulatory blood pressure monitoring is a fundamental tool to diagnose RH, and to check treatment efficacy. The presence of a greater pulse pressure and a lower nocturnal blood pressure reduction in true RH patients may be responsible for this increased cardiovascular risk profile.     

动态血压监测在高血压诊治中的价值

目的分析动态血压监测应用于高血压诊治中的临床价值。方法选取2011年9月-2013年9月接收的高血压患者(研究组)以及血压正常的体检者(对照组)各70例,均分别进行动态血压和常规方式血压监测,对两组采用不同监测方式的24h血压和脉压监测值,以及白天和夜间的血压和脉压监测值分别比较分析。结果研究组在不同监测方式下,24h血压监测值以及白天和夜间血压平均监测值均存在明显性差别(P0.05),对照组则均无明显性的差别(P0.05)。结论动态血压监测应用于高血压诊治中,可对血压进行更准确的监测,利于临床诊治效果的改善和心脑血管疾病等发生率的降低,有重要的应用价值。     

高龄老年高血压患者动态血压特点

目的探讨高龄老年高血压患者动态血压特点。方法选择我院心血管内科及老年医学科住院的高血压患者265例,按年龄分为高龄老年组(年龄≥80岁)94例、老年组(60～79岁)90例和60岁组81例,行动态血压监测,分析其血压节律、3个时段(24h、昼间及夜间)血压均值及血压变异性的特点。结果高龄老年组和老年组杓型血压发生率、24h舒张压、昼间舒张压、昼间平均压、夜间舒张压明显低于60岁组,反杓型血压发生率、24h脉压、昼间脉压、夜间收缩压、夜间脉压明显高于60岁组(P0.05,P0.01);高龄老年组杓型血压发生率及24h、昼间、夜间舒张压明显低于老年组[13.83%vs 26.66%,(66.17±7.39)mm Hg(1mm Hg=0.133kPa)vs (70.39±10.96)mm Hg,(66.90±7.55)mm Hg vs (70.88±11.68)mm Hg,(64.10±8.14)mm Hg vs (68.27±11.86)mm Hg,P0.05,P0.01],24h、夜间脉压明显高于老年组(P0.05,P0.01),昼间收缩压变异明显高于老年组和60岁组,24h收缩压变异高于60岁组,差异有统计学意义(P0.01);老年组24h平均压明显低于60岁组(P0.05)。结论高龄老年高血压患者动态血压表现出血压节律异常、脉压增大、血压变异性升高等特点。     

肾实质性高血压24小时动态血压分析

目的：分析肾实质性高血压24小时动态血压变化。方法：实验组（A组）对象为经临床和实验室检查确诊的肾实质性高血压病人，共52例；对照组（B组）为同期随机抽取的我院52例轻、中度原发性高血压病人。两组均作动态血压检测（ABPM）。结果：A、B两组之间24小时收缩压、舒张压，白天收缩压、舒张压无显著性差异（P〉0．05），夜间收缩压、舒张压则有高度显著性差异（P〈0．01），夜间血压下降率A组收缩压、舒张压均〈10％，B组则〉10％，两组间亦有高度显著性差异（P〈0．01）。结论：肾实质性高血压夜间收缩压、舒张压下降较少，昼夜节律减弱。     

Methods of data analysis of ambulatory blood pressure monitoring in clinical trials

The objectives of the analysis are to compare the blood pressure levels at different phases of the trial and to be sure that the effect will continue until the next dose. There are problems before the analysis for which consensus is necessary. If the overall 24 h study is the first generally recognized stage, it is difficult to know how to take into account the circadian rhythm: one could determine a day phase and a night phase arbitrarily, one could rely upon the diary of the patient or calculate by using a model of the two phases of individual diurnal rhythms. Analysis of shorter periods reduces the reproducibility of ABPM: what minimum period os sufficiently reproducible (3-4 h for example)?. The methods of statistical analysis of the levels of blood pressure are dictated by the conditions of application of the tests. If a normal distribution is confirmed, the use of parametric tests is required (Student's paired t-test in cross-over studies, analysis of variance for repetitive measures and to investigate the interaction between treatment and time). Non-parametric tests are required for non-continuous distributions (the Wilcoxon test for example). The study of effect over time as performed classically by the peak-trough method poses many problems of analysis. Over what time period should one quantify the peak and the trough?. How should one integrate the placebo effect into a parallel group study?. Is it necessary to calculate the individual peaks and troughs and then take the mean of these or would it suffice to perform a global calculation?. It might be necessary to perform subgroup analyses in order to evaluate the real effects of treatment. How then should one define responders?. Taking into account the 'white-coat' effect and compliance with treatment demands more rigid inclusion and exclusion criteria than do other methods of analysis and limits the validity of the sample.     

Diagnostic accuracy of home vs. ambulatory blood pressure monitoring in untreated and treated hypertension

Several studies with relatively small size and different design and end points have investigated the diagnostic ability of home blood pressure (HBP). This study investigated the usefulness of HBP compared with ambulatory monitoring (ABP) in diagnosing sustained hypertension, white coat phenomenon (WCP) and masked hypertension (MH) in a large sample of untreated and treated subjects using a blood pressure (BP) measurement protocol according to the current guidelines. A total of 613 subjects attending a hypertension clinic (mean age 53±12.4 (s.d.) years, men 57%, untreated 59%) had measurements of clinic BP (three visits, triplicate measurements per visit), HBP (6 days, duplicate morning and evening measurements) and awake ABP (20-min intervals) within 6 weeks. Sustained hypertension was diagnosed in 50% of the participants by ABP and HBP (agreement 89%, κ=0.79), WCP in 14 and 15%, respectively (agreement 89%, κ=0.56) and MH in 16% and 15% (agreement 88%, κ=0.52). Only 4% of the subjects (27/613) showed clinically significant diagnostic disagreement with BP deviation >5?mm?Hg above the diagnostic threshold (for HBP or ABP). By taking ABP as reference, the sensitivity, specificity, positive and negative predictive value of HBP in detecting sustained hypertension were 90, 89, 89 and 90%, respectively, WCP 61, 94, 64 and 94% and MH 60, 93, 60 and 93%. Similar diagnostic agreement was found in untreated and treated subjects. HBP appears to be a reliable alternative to ABP in the diagnosis of hypertension and the detection of WCP and MH in both untreated and treated subjects.