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Pharmacy blood pressure: a common, useful, and neglected out of office blood pressure measurement method

Stergiou, George S.; Kyriakoulis, Konstantinos G.; Kollias, Anastasios

doi: 10.1097/HJH.0000000000001466
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Hypertension Center STRIDE-7, National and Kapodistrian University of Athens, School of Medicine, Third Department of Medicine, Sotiria Hospital, Athens, Greece

Correspondence to Prof George S. Stergiou, MD, FRCP, Hypertension Center STRIDE-7, National and Kapodistrian University of Athens, School of Medicine, Third Department of Medicine, Sotiria Hospital, 152 Mesogion Avenue, Athens 11527, Greece. Tel: +30 2107763117; fax: +30 2107719981; e-mail: stergiougs@gmail.com

Blood pressure (BP) measurement in people visiting community pharmacies (PhaBP) is widely used in most countries, yet its exact extent is largely understudied. In a survey in 708 community pharmacists in Japan, 54% answered that an automatic monitor for patient BP measurement was available in their pharmacy, and 36% recommended to hypertensive patients to have their BP measured in the pharmacy [1]. On the other hand, numerous studies and systematic reviews investigated the role of pharmacists as partners to the healthcare system for hypertension management, not simply for PhaBP measurement and the identification of uncontrolled hypertension, but also for improving long-term treatment compliance and hypertension control and even treatment titration [2–4].

The WHO has recognized the considerable potential of pharmacists to improve hypertension control at the community level and produced a document addressed to community pharmacists to be used as a guide for organizing pharmacy-based work in hypertension management [5]. This initiative aimed at establishing a pharmacy-based hypertension management model including three levels: (i) primary prevention of hypertension by providing advice on healthy lifestyles, (ii) early detection of hypertension by measuring undiagnosed individuals and referral to primary care doctors, and (iii) management of treated hypertensive patients with regular BP measurement in the pharmacy.

The WHO recommended running training courses on hypertension for pharmacists at national and local level [5]. The use of accurate BP monitors was recommended, including auscultatory sphygmomanometers (mercury or aneroid), or automated devices that have been internationally validated, and provided a list of specific brands and models. Recommendations were also provided for cuff sizes to fit the arm of each individual, and for the conditions of PhaBP measurement (relaxed, 5-min sitting rest, arm supported at heart level), yet no instructions for the number of measurements were given. A threshold at 140/90 mmHg was proposed for defining uncontrolled hypertension based on PhaBP measurements [5].

The US Centers for Disease Control and Prevention also recognized the important role of pharmacists in the management of hypertension and developed a resource guide presenting an overview of high BP, guidance for accurate BP measurements and devices, and five steps of the Pharmacists’ Patient Care Process for hypertension management [6]. However, no threshold for hypertension based on PhaBP measurement was proposed.

In this issue of the Journal, Albasri et al.[7] presented a meta-analysis of the published evidence (eight studies, N = 2319) on BP measurements taken in community pharmacies versus other BP measurement methods [office BP (OBP), home BP (HBP), ambulatory BP (ABP)]. The authors concluded that the current evidence is rather uncertain, yet they proposed the 135/85 mmHg threshold as reasonable for hypertension diagnosis based on PhaBP measurements [7].

This is the first systematic review and meta-analysis of studies comparing PhaBP with other BP measurement methods. However, these results should be considered by taking into account several important limitations [7]. First, one of the eight studies included 60% of the participants (N = 1399). Second, for the primary endpoint (PhaBP versus daytime ABP) data from only 319 patients (14%) were used. Third, there was considerable heterogeneity among studies in almost all the comparisons, which was mainly due to inconsistent BP measurement methodology regarding (i) the observer (OBP by doctor, or nurse, or automated unattended with patient alone during measurements; PhaBP by pharmacist, or assistant, or unattended kiosk), (ii) the BP monitor type and cuff in each study and each patient when measured with different methods, (iii) the BP measurement conditions for each method, and (iv) the BP measurement protocol (number of visits and measurements per visit for PhaBP and OBP; number of days and measurements per day for HBP; exclusion of first readings in some studies). Fourth, a quality assessment checklist for the methodology of the studies included in the meta-analyses showed high risk of bias or applicability concerns in 38 of 72 assessments (53%) [7]. The authors of this article have been very careful in identifying all the above sources of bias and attempted to quantify their impact by performing sensitivity analyses [7].

The main conclusions of this meta-analysis are that PhaBP: (i) does not differ from daytime ABP, (ii) is higher than 24-h ABP, (iii) does not differ from HBP, and (iv) does not differ from OBP. Indeed, the comparison versus daytime ABP (primary endpoint) was the least problematic, with 95% confidence intervals (CIs) excluding a clinically important difference (>5 mmHg), even after excluding studies with questionable methodology [7]. Also, the comparison versus HBP was consistent, with 95% CIs excluding a clinically important difference (>5 mmHg), even after excluding questionable studies. These data do support the conclusion of the authors to use the same hypertension threshold (135/85 mmHg) for PhaBP as for HBP and daytime ABP [8–10]. This proposal is further supported by the rather uncertain results regarding the PhaBP versus 24-h ABP difference, although the 95% CIs were wide and included a clinically unimportant difference (<5 mmHg) [7].

The results for PhaBP versus OBP are problematic [7]. According to the findings mentioned above, PhaBP should be lower than OBP, yet no such difference was found. Analysis after exclusion of studies with questionable methodology again showed no difference, yet this time a clinically important difference (PhaBP being lower than OBP) was not excluded. It should be noted, however, that the largest study that provided 66% of the participants in this analysis did show PhaBP to be significantly lower than OBP [7]. These uncertain findings are probably attributed to the abovementioned several sources of heterogeneity in the OBP methodology, involving the observer, devices, measurement protocol, and others. ABP and HBP are more standardized methods in terms of devices (automated) and observers (self-measured HBP and automated ABP) and are known to provide more reproducible BP values, which can identify BP differences with higher accuracy [11].

As mentioned above, it is quite long time since the WHO has recognized the important role that the pharmacists can play in the management of hypertension in the community [5]. The pharmacist is usually close to the patient's home, does not require an appointment and does not charge for a visit [12]. PhaBP is one more method for BP measurement which is widespread and therefore, has considerable potential to contribute in hypertension detection and management. The meta-analysis by Albasri et al.[7] on PhaBP measurement provided two new and important pieces of information: first, the PhaBP threshold for hypertension appears to be similar to that of the other two out of office BP measurement methods (HBP and daytime ABP) [8–10] and of the automated unattended OBP (135/85 mmHg) [13] (Table 1). This threshold needs to be adopted by the WHO that currently recommends the 140/90 threshold for PhaBP measurements. Second, the available evidence is limited and heterogenous and more research is needed to clarify key aspects of the method, including its reproducibility, the optimal measurement schedule, the threshold for hypertension diagnosis, the diagnostic agreement versus the other out of office BP measurement methods, and its usefulness and cost-effectiveness as a screening method for detecting hypertension and in the long-term management of treated hypertension. Until more data become available, PhaBP should be widely applied as a screening method for detecting both undiagnosed and uncontrolled hypertension, using validated automated arm cuff devices and triplicate measurements and with the 135/85 mmHg threshold.

TABLE 1

TABLE 1

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ACKNOWLEDGEMENTS

Conflicts of interest

There are no conflicts of interest.

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REFERENCES

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