Pharmacist Outreach About Measuring Blood Pressure at Home Can Help Reveal Masked Hypertension
Masked hypertension presents quite a challenge. How do doctors determine which patient with normal blood pressure during an office exam might have high blood pressure readings at home? Or how do they convince a patient with seemingly normal blood pressure to pay out-of-pocket for ambulatory blood pressure monitoring, just in case?
It’s an intriguing conundrum that needs to be solved because masked hypertension contributes to target organ damage long before sustained hypertension is diagnosed. Pharmacists can help catch this elusive condition by educating patients about masked hypertension when they dispense medications and when they sell blood pressure monitors.
Current Knowledge and Impact of Masked Hypertension
The use of ambulatory blood pressure monitoring (ABPM) and home blood pressure monitoring (HBPM) led to the unexpected discovery of masked hypertension, which is the opposite of white-coat hypertension. Masked hypertension exists when blood pressure (BP) readings are normal in the doctor’s office or clinic, but elevated outside the clinic.
The task of identifying masked hypertension as early as possible is taking on a sense of urgency. Obviously, it takes a diagnosis and subsequent treatment for these patients to avoid serious consequences such as:
- 1 in 5 remain masked more than 5 years
- More than half have sustained hypertension within 5 years
- High prevalence of cardiovascular target organ damage occurs before transition to sustained hypertension
- Masked hypertension puts patients at same risk of cardiovascular and renal complications as sustained hypertension1
In 2008, the prevalence of masked hypertension was estimated to be 7 percent in children and 19 percent among untreated adults.2 A more recent study published in the December 2016 issue of Circulation confirmed an adult prevalence of 16 percent. This number was based on 888 participants—with an average age of 45—who had BP readings taken at three clinic visits and completed one 24-hour ambulatory monitoring.3
It’s also interesting to note that a significant number of patients being treated for hypertension—about 45 percent—present with masked hypertension.4 Experts don’t have an explanation yet, but they’ve found that antihypertensive treatment lowers in-office BP more than ambulatory BP. In patients being treated for hypertension, the condition is called masked uncontrolled hypertension (MUCH).
Targeting Patients at Risk for Masked Hypertension
Ambulatory blood pressure monitoring is the gold standard for diagnosing masked hypertension, but the U.S. Preventive Service Task Force (USPSTF) says that home blood pressure monitoring is also an acceptable method for confirming hypertension.5 Physicians may have to decide what’s more important—insisting on the gold standard or accepting HBPM to accommodate a method that patients can afford. Coverage may change in the future, but as of now, most insurance providers only cover ABPM to verify white-coat hypertension—masked hypertension is not on the list of approved conditions. Patients who can’t pay out-of-pocket for 24-hour ABPM may be able to swing a home blood pressure monitor.
The real challenge is determining which patients need to be screened for masked hypertension. Pharmacists have an advantage—you can directly counsel patients when dispensing medications to treat chronic disease that increases the risk. You could also develop protocols to reach out to patients who meet the following risk factors for masked hypertension:
- Mental stress at home or work
- Cigarette smoking
- Excessive alcohol consumption
- Sedentary, obese individuals
- Chronic disease – metabolic syndrome, diabetes, chronic kidney disease
- Obstructive sleep apnea
- Elevated nighttime BP with or without high daytime BP
- Men more likely than women
Age and being overweight are long-standing risk factors for masked hypertension, but the Circulation study found that younger, normal-weight participants were just as likely to have higher ambulatory BP reading than clinic readings.
Role of Home Blood Pressure Monitoring
As researchers and health professionals learn more about the inaccuracies of in-office BP, home blood pressure monitoring is becoming more accepted in the clinical realm. As one example, the American Heart Association (AHA) recommends home monitoring for patients with hypertension as a way to help health care providers assess treatment efficacy. Even if HBPM is not preferred for diagnosis, it can be used to alert patients and their physicians to the potential presence of masked hypertension, which is better than letting hypertension go untreated.
Once again, pharmacists have an advantage if they sell digital blood pressure monitors. People searching for a monitor should be educated about masked hypertension and advised to give HBPM readings to their physician for interpretation. Be sure to emphasize the need to consult their physician because diagnostic values for masked hypertension may be different than normal BP values.
More importantly, don’t let people purchase a BP monitor without guiding them toward the most reliable device they can afford and teaching them how to use it. The AHA recommends the following:6
- Automatic, cuff-style, bicep monitors — wrist and finger monitors are less reliable.
- Pharmacists should sell only monitors that have been validated.
- Measure around the upper arm to choose the appropriate cuff size.
- Advise patients not to smoke, drink caffeinated beverages or exercise within 30 minutes before measuring BP.
- Patients should sit on a firm chair, with feet flat on the floor, arm supported on a table and at heart level.
- Measure BP at the time of day recommended by their health care professional.
- Digital devices that store BP readings are preferred, otherwise print out the log provided on the AHA web site and give it to patients so they can easily keep a record.
Measuring Blood Pressure at Home Key to Unmasking Hypertension
You can expect some patients to have an “out of sight, out of mind” attitude; others may wonder whether masked hypertension is just another new condition creating problems where none exist. That’s when pharmacists have the challenging yet vital job of assuring them that masked blood pressure has been verified and represents a risk to their health. You may also be able to motivate cooperation by pointing out it’s an opportunity to become proactive members of the team rather than passively relying on the doctor. The bottom line is this: If at-risk patients can afford a home blood pressure monitor, what do they have to lose by keeping track of their own readings?
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- “A Clinical Update on Masked Hypertension,” November 2016, http://www.practiceupdate.com/c/46437/1/2/ ↩
- “Prevalence, Causes, and Consequences of Masked Hypertension: A Meta-Analysis,” September 2008, https://www.ncbi.nlm.nih.gov/pubmed/18583985/ ↩
- “Study Reveals More Individuals May Have “Masked” Hypertension Than Thought,” December 2016, http://www.newswise.com/articles/view/665893/?sc=dwhn ↩
- “Masked Hypertension: A Phenomenon of Measurement,” October 2014, http://hyper.ahajournals.org/content/65/1/16 ↩
- “USPSTF Final Recommendation Statement: High Blood Pressure in Adults: Screening,” October 2015, https://www.uspreventiveservicestaskforce.org/Page/Document/RecommendationStatementFinal/high-blood-pressure-in-adults-screening ↩
- “Monitoring Your Blood Pressure at Home,” November 2016, http://www.heart.org/HEARTORG/Conditions/HighBloodPressure/SymptomsDiagnosisMonitoringofHighBloodPressure/Home-Blood-Pressure-Monitoring_UCM_301874_Article.jsp# ↩