Home Blood Pressure Monitoring: A Call to Action for Pharmacists

Dr. Page is an associate professor of clinical pharmacy and physical medicine and a clinical specialist, Division of Cardiology, University of Colorado Health Sciences Center, Schools of Pharmacy and Medicine.

Over the past decade, thepharmacy profession haschanged dramatically. Moresignificantly, however, is how thepharmacist within both the communityand institutional settings hasbecome a critical interdisciplinaryteam member.¹ Within integratedhealth systems, data suggest thatwhen pharmacists are included asmembers of the health care team,the percentage of patients withhypertension who reach their goalblood pressure (BP) is increased.²Furthermore, drug interactions,patient nonadherence, andoverall direct and indirect costsassociated with hypertensionare also reduced.³

Per the recommendationsof the new Healthy People2010, goals for hypertensionwarrant a more intensive approachin order to achievedesired BP control rates.⁴Achieving these goals in thehypertensive population, however,will be difficult withoutsignificant assistance by pharmacists.⁵ One way pharmacistscan begin impacting thepublic health problem ofhypertension is by becomingeducated advocates for homeblood pressure monitoring(HBPM).

Emphasis on Home Blood Pressure Monitoring

Many criticisms exist regardingoffice-based BP measurements, whichinclude observer variability and training,terminal digit bias, and whitecoathypertension.⁶ When makingtherapeutic decisions, these factorspresent a dilemma for providers. TheSeventh Report of the Joint NationalCommittee on the Prevention, Detection,Evaluation, and Treatment ofHigh Blood Pressure (JNC 7) recommendHBPM.⁷The JNC 7 report indicated thatHBPM can target the following issuessurrounding the pharmacotherapy ofhypertension: increase therapy compliance,evaluate the accuracy ofdiagnosis, validate drug regimen efficacy,reduce treatment costs, andeducate patients. Furthermore, HBPMappears ideal to overcome difficultiesin interpreting office BP readings.Unfortunately, HBPM is often not routinelyused. In fact, patients receivelittle education from their primarycare providers regarding HBPM.^8-12

Value for the Patient

Home BP monitors are relativelyaffordable, especially consideringthe value of the informationthey deliver. These devicescan provide a visual cueand a positive reinforcementtool for drug adherence, forexample. By recording and documentingfluctuations in BP, ahome monitor can assist indetermining an appropriatedrug-dose interval, as well asevaluate the efficacy of therapeuticmodifications. This informationin turn reinforces to thepatient the advantages of goodBP control and an overallunderstanding of the diseaseitself. Increased awarenessmay provide better compliancewhile potentially decreasing theincidence of the deadly, long-termconsequences of uncontrolled hypertension.^12-14

Pharmacists' Role

Community pharmacists are uniquelypositioned to overcome thebarriers associated with officebasedBP measurement. Home BPmonitors are typically sold in communitypharmacies. Moreover, patientsvisit their pharmacy almostmonthly to pick up their antihypertensivemedication, more frequentlythan any other health care facility.¹⁵Furthermore, collaborative relationshipsare being developed betweenphysicians and community pharmaciststo improve hypertension management.¹⁶The Hypertension OutcomesThrough Blood Pressure Monitoringand Evaluation by Pharmacists(HOME) study found that patientswho received education regardingtheir hypertension, as well as instructionregarding use of a homeBP monitor from a community pharmacisthad a statistically significantlower diastolic BP, compared withthose patients who received theirBP evaluation solely from their primarycare provider.¹⁷

Types of Home Blood Pressure Monitors

The 3 major configurations of BPmonitors available for home useinclude aneroid manometers, semiautomaticdigital monitors, and fullyautomatic digital devices.¹⁸

The gold standard method formeasuring BP is the mercury sphygmomanometer,which measures BPwith a plastic or glass tubular gauge,a mercury reservoir, and a manuallyinflated cuff. In order to measure BPthis device uses gravity. Thus itsreadings are considered the mostclinically consistent and accurate.¹⁹

The aneroid monitor employs amechanical bellows and lever systemthat requires frequent calibrationto create reliable and accuratereadings. The aneroid monitors arethe least expensive option forpatients, yet they are consideredless accurate, compared with mercurysphygmomanometers.

Unlike the aneroid device, the digitalmonitors come with either asemiautomatic or completely automaticinflatable cuff. These monitorsalmost entirely use oscillometricmeasurement in order to determineBP. Small oscillations or changes incuff inflation obtain the mean systolicand diastolic pressure. Thesereadings are calculated by using aset of percentages that vary dependingon the model's manufacturer.The peak amplitude of theoscillations is the mean BP. Systolicpressure is a reference point about55% prior to this peak, and diastolicpressure is approximately at a point85% after the peak.^{10, 12, 14, 20}

Comparisons of Monitors

While the mercury sphygmomanometerand aneroid manometermay be less expensive, they donot lend themselves to home use.For both types of devices, themajority of patients do not possessthe skills and dexterity required touse them, as a stethoscope, mustbe used to auscultate the Korotkoffsounds. Furthermore, for the mercurysphygmomanometer, mercurypresents a potential health hazard ifspilled or if it comes in direct contactwith skin.

The digital monitor appears tohave all the characteristics thatmake it an ideal choice for HBPM.The BP reading is displayed on aneasily readable digital screen designedwith large formats for olderadults with poor eyesight. Mostmonitors will routinely record andstore BP and heartbeat readings,with some having the additionalcapability of downloading the datato a PC for tracking, printing, andeven e-mailing to a health careprovider. Studies have shown thatthese devices demonstrate a highdegree of correlation with auscultationreadings obtained by a practitioneror by oscillometric devices.¹²

These devices range in cost fromabout $40 for a semiautomatic unitto around $99 for a fully featuredautomatic monitor. It is importantthat the home BP monitor pharmacistsrecommend is appropriatelyvalidated as evidenced by publishedclinical studies in peer reviewedjournals. A list of validated monitorsis available at www.bhsoc.org/blood_pressure_list.stm.¹⁴

The FDA-approved Monitor

The first BP devices cleared bythe FDA to detect morning hypertensionare manufactured by OmronHealthcare. One such device is theOmron HEM-780 with IntelliSensetechnology. This device is an automated,upper-arm, oscillometric devicethat measures BP and detectsirregular heartbeats. Its memory willautomatically store BP and pulserateinformation for 2 individuals forup to 84 sets of measurement valuesin addition to weekly morningand evening BP averages per individualfor 8 weeks.

More Information

The Subcommittee on Professionaland Public Education of theAmerican Heart Association Councilon High Blood Pressure Researchhas published guidelines specificallyaddressing the measurement of BP.¹⁴These guidelines can be found atwww.americanheart.org/presenter.jhtml?identifier=3004579. For moreinformation on morning hypertension,visit www.morningbp.com/pt29

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