Treating high BP can reduce the risks of ESKD, but measuring it correctly is key
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“The most important skill you will learn in your medical career is to measure blood pressure. Do it correctly and you will help more patients to better health than with any other skill you learn. Do it wrong and you will harm more patients than with any other medical errors you make over your career.” — Clarence E. Grim, MD
Hypertension or high blood pressure is common, and it is expected to affect more than 1.3 billion people worldwide by 2025.
High BP is also common among patients with chronic kidney disease, with prevalence ranging from 60% to 90% depending on CKD stage and its cause. Conversely, high BP accelerates CKD progression that can lead to kidney failure. Further, high BP is a major cause of CVD in the general and CKD populations. Lowering BP reduces CVD risks in large intervention trials, which further highlights the importance of maintaining optimal BP.
The maintenance of optimal BP requires reliable BP measurements, which is one of the most frequently performed health assessments in the world. Yet, most of the measurements are not performed properly. There are a multitude of reasons why nonstandardized (“casual”) clinic BP measurements are often not accurate or reliable, but most can be attributed to a lack of proper equipment or technique, inadequate patient preparations, and/or inappropriate clinic settings.
Essentially, all large, randomized, controlled outcome clinical trials comparing BP targets that have demonstrated health benefits from BP lowering have employed a standardized protocol with clinically validated devices. Further, all BP guidelines put forth by major organizations have repeatedly recommended and emphasized the importance of standardized clinic BP measurements to minimize errors.
Misdiagnosis
Standardized and reliable laboratory assays for blood analytes, such as blood hemoglobin or serum potassium, are expected by clinicians. Yet, most clinics are still relying on suboptimal, nonstandardized BP measurements, potentially endangering patients by misdiagnosing, over-treating or under-treating high BP. We posit that a major underlying cause of this suboptimal practice is the underappreciation of the importance of standardized BP measurements and a continuing misperception that standardized clinic BP measurements are time-consuming and impractical.
Recently, 13 international organizations convened to issue a consensus statement on standardized clinic BP measurement, highlighting its importance on health outcomes and patient safety. The document further describes the likely reasons why it is not practiced widely, provides a pragmatic measurement protocol that is feasible and can be readily adopted and proposes strategies that can be utilized to address this problem system-wide.
The consensus document outlined the elements that the authors consider to be essential for standardized, reliable BP measurements in the clinic setting.
Firstly, and perhaps most importantly, patients should be properly prepared and informed ahead of time to avoid caffeine, alcohol, nicotine and exercise for at least 30 minutes before BP measurement and to use the bathroom beforehand to avoid discomfort. Patients should also be rested for 3 to 5 minutes before the procedure and not engage in any conversations.
Secondly, proper physical environment and equipment are required. The BP measurement station should be in a quiet room at a comfortable temperature. A validated BP measurement device and a range of cuff sizes to accommodate various upper-arm sizes should be available. The BP measuring device can be a traditional sphygmomanometer or an automated machine, although the latter confers additional advantages.
Thirdly, only a health care provider fully trained, and retrained annually, in BP measurement should perform the procedure.
Lastly, the trained provider should explain to the patient about the procedure beforehand and obtain two or more measurements, 30 seconds apart, with these values averaged and recorded as the final value for that episode.
Although these steps were designed for BP measurements in the clinic setting, most are probably also important in the home or other out-of-clinic settings.
Barriers
Authors of the consensus statement understand that, for the standardized BP measurement procedure to be widely adopted, it must be pragmatic, and clinicians may choose to tailor the procedure to their specific individual settings. Below are several perceived barriers to implementation, as well as suggested solutions.
Myth 1: It is too time-consuming to perform standardized BP measurement.
Both the Kaiser Permanente Hypertension Program and San Francisco Health Network clinics have found that the additional time needed to perform standardized BP measurement is minimal if the clinic workflow is streamlined with an automated BP monitor. Other studies have also reported that a transition to automated measurements saved 1.5 hours per week for a full-time primary care provider, because automated machines potentially free up time for clinic personnel to perform other tasks.
Myth 2: Implementing a system-wide standardized BP measurement protocol is not feasible.
The adoption of the “measure accurately, act rapidly, and partner with patients” (MAP) protocol across 16 community-based family medicine clinics in South Carolina demonstrated a significant system-wide improvement in BP control in up to 75% of patients with hypertension (more than 12,300 patients) at 12 months. Furthermore, implementation of the MAP protocol using an automated monitor in the absence of clinical personnel (“unattended” measurement) was preferred by the personnel, and clinicians expressed greater confidence in the MAP readings, demonstrating that not only is implementation of a system-wide protocol feasible, it is also beneficial to both patients and health care providers.
Myth 3: Low-resource health care systems would struggle to implement standardized BP measurement.
The scarcity of BP monitors, suboptimal clinic environment and shortage of health care workers may indeed pose barriers to implementation. However, a recent WHO Global Hearts Initiative, which aims to improve BP accuracy by promoting a simplified and standardized protocol with validated devices, demonstrates that incremental success can be achieved if the program is well-planned, progressive and inclusive. Team-based approaches involving nonphysician personnel may be a preferable alternative for countries where physicians currently execute all tasks related to BP measurement and management.
Implementation
The consensus statement highlighted the following six items in its “call to action” that various stakeholders could do to collectively address this issue.
Properly educate health care providers about the large variability of nonstandardized (casual) BP measurement and its negative implications on patient safety. There is no correction factor that can convert a casual BP value to an equivalent standardized one for patient management.
Encourage health care institutions to provide validated, proper BP measurement devices and secure proper clinic space, condition, staffing, time and optimal workflow plan to facilitate the measurement procedure. Health care institutions should also take advantage of electronic health alerts as opportunities to educate patients about and prepare them for standardized measurements.
Convince health care funding agencies (ie, payers) to offer positive and/or negative incentives for adopting standardized clinic BP measurements.
Spur BP monitor manufacturers to provide and maintain BP measuring equipment and cuffs for various populations at a reasonable cost. A table of validated BP monitors compiled by various medical organizations around the world is included in the consensus statement.
Encourage government regulatory agencies to mandate training and certification of staff on standardized BP measurement.
Partner with professional societies to promote the importance of standardized BP measurement to health care providers and the public alike; empower patients by conducting health campaigns to raise awareness and concerns to their treating physician if a BP measurement is not taken properly.
Conclusion
High BP is exceedingly common among patients with CKD and contributes significantly to CVD. Further, high BP accelerates the rate of kidney function decline. Conversely, BP that is too low leads to poor perfusion of the kidney and impairs kidney function. Optimal BP, however, cannot be achieved without first measuring BP reliably. It is hoped that this “call to action” serves as a clarion call to all stakeholders that we must do better in measuring BP because our patients expect and deserve better, and health care providers can, in fact, do better.
- References:
- Cheung AK, et al. Am J Med. 2023;doi:10.1016/j.amjmed.2022.12.015.
- Grim CE, et al. Chapter 9: Office blood pressure management. In Hypertension. A Companion to Braunwald’s Heart Disease (3rd ed.). Elsevier. 2018.
- For more information:
- Alfred K. Cheung, MD, is Dialysis Research Foundation Presidential Endowed Chair, professor of internal medicine, chief of the division of nephrology and hypertension, and vice chair for research in the department of internal medicine at the University of Utah, Salt Lake City. He was the principal investigator of the Utah Clinical Center Network in the Systolic Blood Pressure Intervention Trial, which is sponsored by the NIH. He can be reached at alfred.cheung@hsc.utah.edu.
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