E d i t o r i a l

Professors: The World Is Not Flat

Steven A. Yarows, MD

The cornerstone of hypertension treatment islowering the blood pressure (BP), which

clearly has resulted in improvement in cardiovas-cular outcomes. The decades of research havevalidated this principle, yet the ‘‘bench to prac-tice’’ translation of this research is hampered bydifferent techniques of BP measurement. Themost abundant hypertensive research has been ina clinical research setting in which the patient hasbeen seated for a minimum of 5 minutes and trip-licate readings are measured and averaged. Thisaverage BP is the basis of clinical decisions abouttreatment and clinical cardiovascular outcomesstudies.

In contrast, the vast majority of BP measure-ments occur outside of research settings in an officeby a single measured BP. In this setting in the Uni-ted States, the BP is measured by a medical assis-tant (MA) shortly after the patient is escorted to anexamination room. We need to address the ‘‘ele-phant in the room,’’ that BP measurement withinnonresearch settings is not the same as within aca-demic institutions that utilize research protocols.Perhaps this is often not understood by some aca-demic physicians whose office setting may be quitedifferent. A recent journal submission regarding BPmeasurement had the following criticism by areviewer: ‘‘What is more, in these types of settings,blood pressure measurements are generally madeby nurses and medical support staff trained in thisfield, not by medical assistants.’’ Certified MA areinitially trained in proper BP measurement

techniques, however this may not translate intolater actual practice. Additionally, many practicesdo not employ personnel that have this specific BPmeasurement training. There is scant discussion byhypertension specialists about this difference intechniques and the clinical importance of this.

Some observations have indicated higher measure-ments from ‘‘usual’’ methods by 6.2 to 15.5 ⁄4.7 to11.6 mm Hg compared to ‘‘research nurses,’’1–3

which is a potentially clinically significant variance.The common doctrine of physician-measured BP ishigher by 6 to 10 mm Hg for systolic BP and 8 mmHg for diastolic BP than ‘‘nurse’’ measured read-ings.4,5 Therefore, it is believed that physician-mea-sured BP will be higher than MA-measured BP innonacademic offices. Is this correct?

My 28 years of clinical experience indicateotherwise. I performed a retrospective, electronicchart review of 888 patients from my practice overan approximate 10 month period to investigate thisobservation. I found that the MA average BP was9.4 ⁄6.8 mm Hg higher than the physician readings(P<.05). The MA-measured, systolic BP readingswere �140 mm Hg whereas the physician-mea-sured readings were under this threshold 27.0% ofthe time. The MA-measured diastolic was �90 mmHg, whereas the physician-measured readings werealso under this criteria in 16.0% of patients. Therewas a �15 mm Hg difference between the MA andphysician readings in 38.5% of systolic and 34.8%of diastolic measurements. If the treatment deci-sions were based on the MA readings, a significantamount of patients would have incurred an inap-propriate medication change.

This was not a randomized, controlled trial andthere were many potential factors that could haveresulted in the differences. The most likely factorswere that the physician readings were performedafter a longer period of rest in the examination

From Chelsea International Medicine, Chelsea, MIAddress for correspondence:Steven A. Yarrows, MD, Chelsea InternationalMedicine, 128 Van Buren Street, Chelsea, MI 48118E-mail: steven_yarows@ihacares.com

doi: 10.1111/j.1751-7176.2010.00314.x

THE JOURNAL OF CLINICAL HYPERTENSION VOL. 12 NO. 8 AUGUST 2010568

room, and use of a proper-sized, large cuff.I believe that this is not unique to my practice andmay in fact occur in most nonresearch practices.

Additionally, we should acknowledge that pri-mary care physician practices are designed for highvolume, expense-restricted visits due to significantoverhead and current low reimbursement rateswhich may be compounded by the anticipatedshortage of providers. A proper BP measurementshould take approximately 1 minute (assuming arange of 130 mm Hg at 2 mm Hg ⁄ second defla-tion), which would be 7% to 10% of the allottedoffice visit, not accounting for the suggested mini-mum of 5 minutes of rest and triplicate readings(53%–80% of the visit). This is not feasible due tolimited examination room space. Using calibrated,automatic devices that take repetitive readings hasbeen demonstrated to be accurate compared toawake ambulatory BP monitoring.6–8 Unfortu-nately, these devices are currently expensive andwould increase the patient time within the exami-nation room.

Could future BP measurement devices be usedprior to the visit in the lobby during the patientwait? I asked 235 patients to measure BP beforeand after a physician visit in the waiting room ofmy office using an automatic BP monitor andfound no significant difference in the average read-ings (0 ⁄0 mm Hg, P>.05) before and after the visit,indicating that the readings were reproducible.These waiting room devices would need to have aminimum 5 minute relaxation period prior to thefirst reading and automatically average the triplicatereadings. Proper cuff size would have to be assured.The readings could be transmitted to an electronicmedical record or recorded for paper charts. Con-ceptually this is feasible, as most patients wait priorto being taken to the examination room. The ques-tion that remains: is this accurate?

When Columbus tried to tell other learned peoplethat the ‘‘World is not flat,’’ this was met with skep-ticism. We need to drop any skepticism that BP ismeasured in primary care offices the same as inresearch settings and determine how to address this

problem. So how do we validate the best method toaccurately measure BP within a clinical primary careoffice? Now is an excellent time to look at workflowwithin offices, as progressively more primary careoffices are converting to electronic medical records,greatly necessitating workflow changes. I would liketo organize interested people to design and imple-ment appropriate research to address this issue. Ifyou have interest, please contact me at: steven_yarows@ihacares.com. Dr Thomas Pickering statedin 1994 that ‘‘the measurement of blood pressure ismuch too serious to be left to physicians.’’9 Perhapsin a nonresearch clinical practice this should beamended to ‘‘the measurement of blood pressure ismuch too serious to be left to medical assistants’’that usually do not have time to properly measurethe BP. A 30% overdiagnosis of hypertension forsystolic BP is unacceptable.

REFERENCES

1 Kay LE. Accuracy of blood pressure measurement in thefamily practice center. J Am Board Fam Pract. 1998;11:252–258.

2 Rocha JC, Rocha AT, Magossi AMG, et al. Evaluation ofthe technique for taking blood pressure by health careworkers in an university hospital. Division of Hypertension,University of Campinas, Campinas, Brazil. Am J Hypertens.1998;11(Part 2):66A.

3 Campbell NRC, Myers MG, McKay DW. Is usual measure-ment of blood pressure meaningful? Blood Press Monit.1999;4:71–76.

4 Gerin W, Marion RM, Friedman R, et al. How should wemeasure blood pressure in the doctor’s office? Blood PressMonit. 2001;6:257–262.

5 Batide-Alanore AL, Chatellier G, Bobrie G, et al. Compari-son of nurse- and physician-determined clinic blood pres-sure levels in patients referred to a hypertension clinic:implications for subsequent management. J Hypertens.2000;18:391–398.

6 Myers MG, Valdivieso M, Kiss A. Use of automated officeblood pressure measurement to reduce the white coatresponse. J Hypertens. 2009;27:280–286.

7 Beckett L, Godwin M. The BP TRU automatic blood pres-sure monitor compared to 24 h ambulatory blood pressuremonitoring in the assessment of blood pressure in patientswith hypertension. BMC Cardiovasc Disord. 2005;5:18.

8 Myers MG, Valdivieso M, Kiss A, et al. A comparison oftwo automated sphygmomanometers for use in the officesetting. Blood Pressure Monit. 2009;14(3):108–111.

9 Pickering TG. Blood pressure measurement and detectionof hypertension. Lancet. 1994;344:31–35.

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