— Home-monitoring threshold proposed by American guidelines now supported by U.S. data
People measuring blood pressure (BP) at home should use the threshold of 130/80 mm Hg as proposed by American guidelines to identify hypertension, a study confirmed.
White, black, and Hispanic patients with home BP around 130/80 mm Hg without antihypertensive medications also tended to have the same reading in the clinic. A slight difference existed in which a home BP of 135/85 mm Hg was equivalent to the 140/90 mm Hg clinic BP threshold for stage 2 hypertension.
In terms of outcomes, untreated patients shared the same risks associated with stage 1 hypertension whether their systolic BP crossed the 130 mm Hg cutoff by clinic or home measurement, according to Wanpen Vongpatanasin, MD, of the University of Texas Southwestern Medical Center in Dallas, and colleagues.
Writing online in Hypertension, the researchers concluded that overall, the results of both these regression- and outcome-derived approaches support the home BP thresholds proposed by the 2017 guidelines from American College of Cardiology (ACC)/American Heart Association (AHA).
Home monitoring is one answer to concerns about the "white coat phenomenon," associated with a rise in BP when patients visit the clinic. "Home BP measurement has the advantage over ambulatory BP monitoring because it is more practical, widely available for clinical use, and of lower cost," the investigators added.
Writing in an accompanying editorial, Paul Muntner, PhD, of the University of Alabama at Birmingham, and Daichi Shimbo, MD, of Columbia University in New York City, said it is important that home systolic BP measurements corresponding to a reading of 130 mm Hg in the clinic consistently stayed at 130 mm Hg for whites, blacks, and Hispanics, as well as for patients taking and not taking antihypertensive medication.
The study was based on treated and untreated individuals ages 30-65 in the Dallas Heart Study (DHS; n=5,768) and North Carolina Masked Hypertension cohort (NCMH; n=420).
"Previous studies have determined diagnostic thresholds for home BP based on outcome-based approaches," Vongpatanasin and co-authors wrote. "However, these BP cutoffs were derived from populations from Japan, Finland, Greece, and Uruguay. None of the data were derived from population-based studies conducted in the United States."
Yet the present study was not without limitations, the team noted: It excluded older persons and enrolled only individuals in the Dallas-Fort Worth and Durham, North Carolina, areas, so the results may not be more widely generalizable.
Muntner and Shimbo said: "Most importantly, home BP in the DHS was not self-measured, because BP readings were obtained by research staff visiting the participants' homes. From this perspective, it is unclear whether the home BP values obtained in this study can be used for the diagnosis and management of hypertension when home BP monitoring is conducted by patients taking their own BP."
The NCMH cohort had a different generalizability problem, the editorialists noted, as it required a standard BP measuring procedure from participants that produced high-quality readings that may be more accurate than what most people get at home.
Muntner and Shimbo stated that the results from Vongpatanasin and colleagues highlight the need for randomized controlled trials that rigorously evaluate the thresholds that should be used to define hypertension status outside of the clinic setting.
European guidelines, which stick to the 140/90 mm Hg office threshold for hypertension, recommend 135/85 mm Hg as the cutoff for hypertension in home monitoring.
Vongpatanasin and co-authors, as well as Muntner and Shimbo, all reported having no conflicts of interest.
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Source Reference: Vongpatanasin W, et al “Diagnostic thresholds for blood pressure measured at home in the context of the 2017 Hypertension Guideline: Analysis from 2 US cohorts” Hypertension 2018; DOI: 10.1161/HYPERTENSIONAHA.118.11657.
Source Reference: Muntner P, Shimbo D "Out-of-clinic blood pressure thresholds for diagnosing and managing hypertension, filling an important evidence gap" Hypertension 2018; DOI: 10.1161/HYPERTENSIONAHA.118.11980.
Read the original article on Medpage Today: Cutoff of 130/80 mm Hg for Hypertension Works at Home Too