Mixed beliefs, practices affect hypertension diagnoses
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Many providers do not follow guidelines to diagnose hypertension, including using the old clinical BP threshold of 140/90 mm Hg instead of the new threshold of 130/80 mm Hg, researchers found.
Another study found that the presence or absence of rest time or an attendant did not affect automated office BP measurements, and that a single set of measurements using the automated office BP method may not be sufficient to diagnose hypertension.
Both studies were presented at the virtual American Heart Association Hypertension Scientific Sessions.
Beliefs on BP measurements
Beverly Green, MD, MPH, family physician at Kaiser Permanente Washington, senior investigator at Kaiser Permanente Washington Health Research Institute and associate clinical professor at the University of Washington School of Medicine, and colleagues assessed provider knowledge, beliefs and practices regarding BP diagnostic tests at 10 primary care medical centers within a single health care system.
“We wanted to understand providers’ knowledge, attitudes and practices around blood pressure measurement and diagnosing hypertension,” Green told Healio. “What was their knowledge as to the proper standards for measuring blood pressure, thresholds for diagnosing hypertension and what do they actually do in practice?”
Surveys were completed by 282 providers, which included medical assistants (n = 102), registered nurses (n = 33), licensed practical nurses (n = 28), advanced practitioners (n = 33) and primary care physicians (n = 86).
“This was done in primary care, so these were primary care internists and family doctors,” Green said in an interview. “We did not survey any cardiologists.”
The study found that most providers reported that manual BP measurements with a stethoscope and ambulatory BP monitoring were very accurate or highly accurate ways to measure BP to diagnose hypertension. Although not listed in the abstract, the belief regarding the accuracy of stethoscopes was reported by 88.9% of nurses/medical assistants and 66.4% of physicians/advanced practitioners, while the belief regarding ambulatory BP was reported by 77.6% of nurses/medical assistants and 93.2% of physicians/advanced practitioners. Most providers also did not believe that home BP, automated clinic BPs or BP measurements from kiosks were highly accurate or very accurate.
“We were surprised that blood pressure measurements taken manually with a cuff and stethoscope was the most trusted method, and most often utilized when making a new diagnosis of hypertension,” Green said in a press release.
Nearly all providers (95.7%) almost always or always relied on clinical BP measurements for new diagnoses of hypertension, although 60.5% of physicians and advanced practitioners would prefer to use ambulatory BP monitoring if it were available.
Survey results were mixed regarding home BP training for patients and if home BP monitors were assessed for accuracy. Physicians and advanced practitioners reported varying schedules of home BP measurements: no schedule (37.3%), 14 days (19.1%) and 7 days (10.9%).
Most physicians and advanced practitioners reported using a clinical BP threshold of 140/90 mm Hg for a new diagnosis of hypertension, and few providers reported using a clinical BP threshold of 130/80 mm Hg. There were also very few physicians and advanced practitioners who reported using home or ambulatory BP monitor diagnostic thresholds based on guidelines, with the most common response being 140/90 mm Hg.
Automated office BP measurements
For another study, Green and colleagues analyzed data from 130 participants aged 18 to 84 years without hypertension diagnosis or treatment despite a high BP, defined as 140/90 mm Hg or higher.
“It was the first study we know of that actually looked at whether automated office blood pressure could be used to diagnose hypertension,” Green told Healio. “All the patients in the study, we found them through the electronic health record that had an elevated blood pressure before we invited them.”
After completing ambulatory BP monitoring, participants were assigned attended automated office BP first and unattended second, or unattended automated office BP first then attended second. Automated office BP was performed twice: after 5 minutes of rest, then again after 15 minutes.
“We wanted to know a couple things: What was the effect of having a staff member in the room vs. out of the room and what was the effect of rest time, no rest vs. 5 minutes vs. longer periods,” Green said in an interview.
Outcomes of interest in this study included within-person difference between attended and unattended BPs, in addition to between 5 and 15 minutes of rest.
Compared with mean daytime ambulatory BP monitoring, automated office BP was significantly lower despite rest or attendance (systolic BP between
3.9 mm Hg and diastolic BP 2.9 mm Hg lower).
Significant within-person differences were not observed in participants to attended automated office BPs compared with those who did not attend (mean difference, 0.1 mm Hg systolic; 95% CI, 0.8 to 1.1; mean difference, 0.2 mm Hg diastolic; 95% CI, 0.5 to 0.8). This also occurred when 5 minutes of rest was compared with 15 minutes of rest (mean difference, 0.5 mm Hg systolic; 95% CI, 1.4 to 0.5; mean difference, 0.2 mm Hg diastolic; 95% CI, 1.2 to 0).
Researchers also assessed the impact of using a daytime mean ambulatory BP monitoring threshold greater than 135 mm Hg/85 mm Hg. This resulted in a sensitivity of 71% and a specificity of 54.1% for a new hypertension diagnosis.
“The guidelines exist because blood pressure is very variable,” Green told Healio. “It varies about 35 points throughout the day, in an average person, systolic and more with somebody with a very high blood pressure. When you bring patients into the clinic and get just one set of measurements, you’re not getting that variation. Even people with very high blood pressure have some normal blood pressure during the day. The answer is to get more blood pressure and to make ambulatory and home BP monitoring more accessible.”
Reference:
- Green B, et al. Presentation MP35. Presented at: American Heart Association Hypertension Scientific Sessions; Sept. 10-13, 2020 (virtual meeting).
Perspective
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Rhonda Cooper-DeHoff, PharmD, MS, FAHA, FACC, FCCP
Hypertension is the most common chronic condition in adults and is associated with substantial morbidity and mortality over the lifetime. While it is modifiable, there remains less than desired BP lowering and BP control overall. In a recent paper published in JAMA (Muntner P, et al. JAMA. 2020;doi:10.1001/jama.2020.14545.), from cross-sectional analyses, it appears that BP control is worsening.
In the first study, it showed that among a group of adults without previous hypertension diagnosis, method of BP measurement in the office (attended vs. unattended) was not impactful on observed BP. The authors concluded that BP measurements from a single office visit are not sufficient to diagnose hypertension. This is consistent with all current guidelines.
The other study provided data suggesting that the physicians, advanced practitioners, licensed practical nurses, registered nurses and medical assistants surveyed were not following evidence-based guidelines for diagnosing hypertension and documented gaps in knowledge, beliefs and practices in the area of treating hypertension.
The findings suggest that there is a lot of work still to be done to improve diagnosing and treating hypertension, which is conferred by recent publications suggesting there is room for improvement in the control of hypertension.
These studies document the need for better information on how to successfully translate guidelines into practice.
Perspective
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Todd Hurst, MD
Almost half of adults have high BP in the U.S., and less than half have it under control. The result is 1,100 preventable deaths each day for a condition we already know how to treat. One of the biggest challenges is knowing what the BP actually is because the traditional way of measuring it in the office is not accurate as measured by the gold standard (24-hour ambulatory BP monitor), as much as 65% of the time.
The current guidelines recommend unattended BP measurement, so the one study provides contrary results. It is a small study, so it should be noted but taken in context of other data. However, its conclusion is supported by research and clinical experience, which is a single office BP may not be sufficient information to make clinical decisions.
The survey study just confirms what we already know. Most health care professionals are not taking BP or treating patients as recommended by the expert guidelines.
Obtaining an accurate BP is challenging but essential to guide clinical recommendations. It is critically important that health care professionals take BP readings correctly.
We need more data on strategies to implement these guideline-recommended processes into busy clinical practices.
Even though the guidelines recommend 24-hour BP monitors, most payers are not reimbursing this except for less common indications. This has to change.
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