A Novel Approach to Office Blood Pressure Measurement: 30-Minute Office Blood Pressure vs Daytime Ambulatory Blood Pressure

Mark C. van der Wel; Iris E. Buunk; Chris van Weel; Theo A. B. M. Thien; J. Carel Bakx

doi:10.1370/afm.1211

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Timing is everything - response to comment of Myers
Mark C. van der Wel

Published on: 06 April 2011
A Novel Approach to Office Blood Pressure Measurement: 30-Minute Office Blood Pressure vs Daytime Ambulatory Blood Pressure.
Willem Jan Verberk

Published on: 06 April 2011
Only five minutes is required to record automated office blood pressure
Martin G. Myers

Published on: 18 March 2011

Published on: (6 April 2011)
Page navigation anchor for Timing is everything - response to comment of Myers
Timing is everything - response to comment of Myers
Mark C. van der Wel, Nijmegen, The Netherlands
Other Contributors:
For the use of serial automated office blood pressure (AOBP) in daily practice a separate room, with comfortable, standardized conditions and the possibility of uninterrupted blood pressure measurements is needed. This will require logistic planning/ organization and we prefer to advise a structural, not ad hoc solution, for this problem. In our view organizing this room will be the major feasibility challenge. Once orga...
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For the use of serial automated office blood pressure (AOBP) in daily practice a separate room, with comfortable, standardized conditions and the possibility of uninterrupted blood pressure measurements is needed. This will require logistic planning/ organization and we prefer to advise a structural, not ad hoc solution, for this problem. In our view organizing this room will be the major feasibility challenge. Once organized the duration of measurement will only affect the maximum number of patients to be measured in a given time.
Our study demonstrated good agreement of 30 min OBPM and daytime ABPM. We have data (to be published) which will support this conclusion in a different set of patients. As mentioned in the discussion section of our article the study of Culleton et al differed greatly from ours. The use of three different measurement devices, the procedure and duration of the complete study protocol and different definitions of daytime ABPM will all have contributed to the differences in study outcome.
It is likely that depending on setting and country (history in types of blood pressure measurements available, guidelines, current use of ABPM devices, financial incentives) users will prefer purpose built devices for AOBP, like BpTru and Microlife WatchBP Office or the use of ABPM devices. We agree with Myers that both the number of readings and the time interval between readings are relevant for a valid AOBP. However we like to add the rest period before taking BP as relevant variable. From figure 1 in our publication we derive that even with one minute interval measurements it will matter at what moment in time these measurements are taken.
In future research we therefore would like to explore the minimum number of readings, the minimum time interval between measurements and the timing of measurements in the natural course of blood pressure required for most valid results. In this evaluation we will have to take both the technological abilities (e.g. with respect to minimum measurement interval) of different types of blood pressure measurement devices and logistic preferences into account. This approach will support widespread use of reliable and functional AOBP despite differences in settings of daily practice.
Competing interests: None declared
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Competing Interests: None declared.
Published on: (6 April 2011)
Page navigation anchor for A Novel Approach to Office Blood Pressure Measurement: 30-Minute Office Blood Pressure vs Daytime Ambulatory Blood Pressure.
A Novel Approach to Office Blood Pressure Measurement: 30-Minute Office Blood Pressure vs Daytime Ambulatory Blood Pressure.
Willem Jan Verberk, Taipei, Taiwan
Van der Wel and colleagues compared 30-minute office blood pressure measurement (OBPM) to daytime ambulatory blood pressure measurement (ABPM) 1. Due to the white coat effect, not following guidelines, observer bias and poor reproducibility the value of “regular” OBPM is limited 2. For this reason a new approach as suggested seems an interesting and good alternative. However, the following items may be considered: 1) Meye...
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Van der Wel and colleagues compared 30-minute office blood pressure measurement (OBPM) to daytime ambulatory blood pressure measurement (ABPM) 1. Due to the white coat effect, not following guidelines, observer bias and poor reproducibility the value of “regular” OBPM is limited 2. For this reason a new approach as suggested seems an interesting and good alternative. However, the following items may be considered: 1) Meyers and colleagues showed that 5 or 10 minutes of readings is sufficient to obtain values similar to daytime ABPM average 3. In addition, from Figure 1 it seems that overall blood pressure (BP) reaches a steady state after 10 minutes. Therefore, 15 minutes of measurement might already be sufficient. It would have been useful if the authors had expanded their analysis and compared different numbers and combinations ofreadings with the average daytime ABPM value. 2) The authors performed 8 BP readings with 5 minute-intervals and decided to calculate the average by discarding the first 2 measurements. This helps to largely eliminate the white coat and cuff response but may not be necessary as previous studies could not demonstrate that discarding the first measurement led to better association with ABPM 3, 4. 3) A great benefit of ABPM is that a patient is measured away from the physician’s office during (limited) normal daily activities and stressful moments, as this is absent with 30-min OBPM it may lead to underestimation of BP values. 4) Some patients used antihypertensive drugs. Although the authors indicate that this does not bias the results, not all antihypertensive drugs provide a long and smooth BP lowering effect 5. Therefore, the time at which 30-min OBPM is assessed may have a significant influence on the BP values. 5) The authors classified patients by hypertensive subtypes. When general OBPMs were lacking they used the first two measurements of the 30-min OBPM. Although this might be comparable with general OBPM the chance to find patients with masked hypertension (MH) is very small since BP values are unlikely to increases after these first two measurements. Notwithstanding the above limitations of 30-min OBPM it reduces or eliminates several important limitations of regular OBPM and therefore most likely provides a more reliable estimation of a patients’ true BP value. However, as BP often cannot be reliably estimated from a single visit a second visit may still be required for optimal diagnosis. Seen in this context one might consider performing self-measurement of BP instead as this leads to more measurements on separate days and might reduce the substantial burden for healthcare workers and patients when leading to less clinical visits 6.
1. van der Wel MC, Buunk IE, van Weel C, Thien TA, Bakx JC. A Novel Approach to Office Blood Pressure Measurement: 30-Minute Office Blood Pressure vs Daytime Ambulatory Blood Pressure. Ann Fam Med 2011;9:128-135. 2. Pickering TG, Gerin W, Schwartz JE, Spruill TM, Davidson KW. Franz Volhard lecture: should doctors still measure blood pressure? The missing patients with masked hypertension. J Hypertens 2008;26:2259-2267. 3. Myers MG, Valdivieso M, Kiss A. Use of automated office blood pressure measurement to reduce the white coat response. J Hypertens 2009;27:280- 286. 4. Graves JW, Grossardt BR. Discarding the first of three nurse- auscultatory or oscillometric blood pressure measurements does not improve the association of office blood pressure with ABPM. Blood Press Monit 2010;15:146-151. 5. Stergiou GS, Efstathiou SP, Skeva, II, Baibas NM, Roussias LG, Mountokalakis TD. Comparison of the smoothness index, the trough : peak ratio and the morning : evening ratio in assessing the features of the antihypertensive drug effect. J Hypertens 2003;21:913-920. 6. Verberk WJ, Kroon AA, Kessels AG, de Leeuw PW. Home blood pressure measurement a systematic review. J Am Coll Cardiol 2005;46:743-751.
Competing interests: Willem Verberk is an employee of Microlife Taipei, Taiwan
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Competing Interests: None declared.
Published on: (18 March 2011)
Page navigation anchor for Only five minutes is required to record automated office blood pressure
Only five minutes is required to record automated office blood pressure
Martin G. Myers, Toronto, Canada
This study examined automated office blood pressure (AOBP) measurement by adapting a 24-hour BP recorder for office use in order to ‘standardize’ the office and out-of-office measurements. This approach limited the shortest time interval between office BP measurements to five minutes which resulted in six readings being taken over a 30-minute period. There are several concerns about this prolonged period being needed...
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This study examined automated office blood pressure (AOBP) measurement by adapting a 24-hour BP recorder for office use in order to ‘standardize’ the office and out-of-office measurements. This approach limited the shortest time interval between office BP measurements to five minutes which resulted in six readings being taken over a 30-minute period. There are several concerns about this prolonged period being needed to record office BP.
Thirty minutes is too long to be feasible for routine clinical practice. Previous research (Culleton et al, BP Monitoring 2006;11:37-42) has shown that recording BP over 25 minutes can give readings which are ‘basal’ and not ‘casual’. That is, the AOBP is substantially lower than the awake ambulatory BP. For some reason, AOBP readings taken over 30 minutes in the present study were similar to the awake ambulatory BP. I cannot explain the difference between the two studies which used similar protocols although differences in patient populations may have been a factor.
Other studies using the BpTRU and SpaceLabs 90207 ABPM recorder have shown similar decreases in office BP recorded over 5 to 10 minutes with the patient being alone, without any 5 minute antecedent period of rest. The SpaceLabs recorder has been used in numerous clinical trials involving many thousands of patients. Both this device and the BpTRU have passed independent validation studies. If there is any difference between AOBP and awake ambulatory BP because of the use of different devices, such differences are almost certainly very small, likely in the range of 1 mmHg.
It seems that the number of automated readings is more important than the time interval between readings. There would be no advantage in recording BP every five minutes if the elimination of the white coat response can be achieved by recording BP every one to two minutes, as has been shown in previous studies. In our most recent study in hypertensive patients, AOBP readings taken at one-minute intervals were similar to the mean awake ambulatory BP obtained using the SpaceLabs 90207 device (BP Monitoring 2010;15:300-304).
Thus, this study confirms that AOBP can be used to reduce or eliminate the white coat response with the mean office BP being similar to the awake ambulatory BP. However, it is not necessary to take readings every five minutes using a 24-hour ABPM device in the office setting. Other devices specifically designed for professional use in the office such as the BpTRU, Omron HEM 907 and Microlife WatchBP Office are available to record AOBP over a much shorter period (5 to 10 minutes) which is more feasible for routine clinical practice.
(A review of AOBP up to 2010 by Myers et al can be found in: Hypertension 2010;55:195-200)
Competing interests: None declared
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Competing Interests: None declared.