(DURHAM, NC) Blood pressure measured at home is a better predictor of heart disease risk than blood pressure (BP) measured during doctor visits, but finding time to review a long list of home blood pressure readings during primary care appointments can be a challenge.
A new study from Duke University School of Medicine and the University of North Carolina at Chapel Hill examines a potential solution: a simplified method called "home BP load."
Rather than calculating an average from multiple readings, the approach focuses on the percentage of readings that exceed a certain threshold, such as 130 mmHg. For example, if half of a patient’s home measurements are above that mark, it’s likely their average blood pressure is too—indicating an increased risk for heart attack and stroke.
The approach could help busy clinics quickly assess the treatment needs for the millions of U.S. adults with high blood pressure, also known as hypertension.
The study, published in the Journal of Hypertension, involved a racially diverse group of 420 adults who measured their blood pressure at home twice a day for ten days. Researchers found that home BP load predicted with 90% accuracy a patient’s overall blood pressure, even when using as few as three days of data.
Anthony J. Viera , MD, professor and chair of the Duke Department of Family Medicine and Community Health , and Alan L. Hinderliter, MD , a cardiologist at UNC Health, led the study.
"Office blood pressure readings (are) just a one-point-in-time measurement that may not represent a person’s true average BP," Viera said. "Repeated BP measurements outside the office give us a more comprehensive picture of a patient’s blood pressure status."
Blood pressure that’s 130 mmHg or higher and stays high can damage arteries and the heart. High blood pressure usually has no signs or symptoms. Often the only way to know if someone has high blood pressure is if it’s checked.
Health care providers use home blood pressure readings to diagnose hypertension and to know if treatments to control blood pressure are working. By simplifying the process of analyzing home blood pressure readings, home BP load could help clinicians make more accurate treatment decisions and ultimately improve patient outcomes, according to the study.
"Most of the time, clinicians are tasked with trying to average a list of blood pressure measurements brought in by patients," Viera said. "These lists can sometimes be quite lengthy, which makes it time-consuming during a busy and brief office visit. This approach—counting the number of readings above threshold—is much simpler."
A key strength of the study was its inclusion of Black patients, who accounted for 90 of the participants. Black Americans have some of the highest rates of high blood pressure in the world . Most participants in the study were under 60 years old and had at least one elevated blood pressure reading during a primary care visit.
However, the findings may not be fully applicable to older adults, patients with multiple health conditions or those with less consistent monitoring habits.
The study was funded by a grant from the National Heart, Lung and Blood Institute (grant R01 HL098604) with additional support provided through grant UL1 RR025747 from the National Institutes of Health.
Additional authors included Feng-Chang Lin; Yumei Yang; Laura A. Viera, and Emily Olsson; and Raven Voora of UNC-Chapel Hill and the Gillings School of Global Public Health.