A study led by Johns Hopkins Medicine researchers concludes that commonly used ways of positioning the patient’s arm during blood pressure (BP) screenings can substantially overestimate test results and may lead to a misdiagnosis of hypertension.
Researchers found that BP measurements obtained with arm positions frequently used in clinical practice — an arm on the lap or unsupported at the side — were markedly higher than those obtained when the arm was supported on a desk, the standard, recommended arm position.
Supporting the arm on the lap overestimated systolic BP — the top number of a reading, or the force of blood flow when pumped out of the heart, by 3.9 mmHg and diastolic blood pressure — the bottom number, or the pressure in the arteries when the heart rests between beats, by 4.0 mmHg.
“If you are consistently measuring blood pressure with an unsupported arm, and that gives you an overestimated BP of 6.5 mmHg, that’s a potential difference between a systolic BP of 123 and 130, or 133 and 140 — which is considered stage 2 hypertension,”Sherry Liu, M.H.S., an Epidemiology Research Coordinator at the Welch Center
An unsupported arm at the side overestimated systolic by 6.5 mmHg and diastolic by 4.4 mmHg.“If you are consistently measuring blood pressure with an unsupported arm, and that gives you an overestimated BP of 6.5 mmHg, that’s a potential difference between a systolic BP of 123 and 130, or 133 and 140 — which is considered stage 2 hypertension,” says Sherry Liu, M.H.S., an epidemiology research coordinator at the Welch Center for Prevention, Epidemiology, and Clinical Research, Department of Epidemiology, at Johns Hopkins Bloomberg School of Public Health and study author.
Investigators caution that their study results may only apply during screenings with automated BP devices, and may not apply to readings done with other BP devices.
However, Brady says, the findings suggest that clinicians need to pay better attention to best practice guidelines, and that patients “must advocate for themselves in the clinical setting and when measuring their BP at home.”
Along with Brady and Liu, authors from Johns Hopkins are Di Zhao, Ahmed Sabit, Chathurangi Pathiravasan, Junichi Ishigami, Jeanne Charleston, Edgar Miller III, Kunihiro Matsushita and Lawrence Appel.
This study was supported by Resolve to Save Lives, which is funded by Bloomberg Philanthropies, the Bill and Melinda Gates Foundation and Gates Philanthropy Partners, which is funded with support from the Chan Zuckerberg Foundation.
(Newswise/ADS)