Between 44.4 million and 53.7 million adults have masked asleep hypertension, according to the first national estimates.
Asleep hypertension — high blood pressure (BP) without high clinic BP — has been shown to be associated with an increased risk for all-cause mortality and cardiovascular disease, even after accounting for clinic BP, Yiyi Zhang, PhD, Columbia University, New York City, told theheart.org | Medscape Cardiology.
“The high prevalence of masked asleep hypertension found in this study suggests it may account for a substantial proportion of cardiovascular disease risk in the US,” said Zhang.
The study was published online October 28 in JAMA Cardiology.
A Hidden Epidemic?
The findings are based on pooled data from 3000 adults (mean age, 52 years; 37% men) from four US population-based studies that included 24-hour ambulatory BP monitoring and 17,969 participants (mean age, 47 years; 48% men) from the 2011 to 2016 National Health and Nutrition Examination Survey (NHANES) without ambulatory BP monitoring data.
The researchers estimated the prevalence of masked asleep hypertension in US adults using BP thresholds from the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC7) and the 2017 American College of Cardiology-American Heart Association (ACC-AHA) BP guidelines.
High clinic BP was defined as at least 140/90 mm Hg using the JNC7 and at least 130/80 mm Hg using the 2017 ACC-AHA guidelines.
High asleep BP was defined as mean asleep BP of at least 120/70 mm Hg for JNC7 and at least 110/65 mm Hg for the 2017 ACC-AHA guidelines. Masked asleep hypertension was defined as high asleep BP without high clinic BP.
Based on the JNC7 guideline, an estimated 18.8% (44.4 million) of US adults have masked asleep hypertension; the estimated prevalence is higher at 22.7% (53.7 million) using the 2017 ACC-AHA guidelines.
Using the 2017 ACC-AHA guidelines, masked asleep hypertension was more common among adults 65 years and older (24.4%), men (27.0%), non-Hispanic Blacks (28.7%), those on antihypertensive medication (24.4%), those who had masked daytime hypertension (44.7%), and those with diabetes (27.6%), obesity (24.3%), or chronic kidney disease (21.5%).
The estimated prevalence of isolated masked asleep hypertension (high asleep BP without high clinic BP or high awake BP) was 11.9% (28.2 million) by JNC7 criteria and 13.3% (31.5 million) by ACC-AHA criteria, the authors report.
“Screening for asleep hypertension is not currently recommended by the US guidelines,” Zhang told theheart.org | Medscape Cardiology.
“These results underscore the potential importance of using ambulatory blood pressure monitoring to not only confirm a diagnosis of hypertension, but to identify other high-risk blood pressure phenotypes, such as asleep hypertension. Also, more data are needed on the cardiovascular risk reduction benefits of treating asleep hypertension,” Zhang said.
Experts Weigh In
Commenting on the study for theheart.org | Medscape Cardiology, Robert Carey, MD, professor of medicine, University of Virginia, Charlottesville, said, “The study is very well done by an excellent group with a high reputation in the area of blood pressure measurement and it really, in a way, opens up a completely new entity that we need to learn more about.
“This has never been really described before in depth,” Carey added.
Also weighing in on the results, Yuichiro Yano, MD, Duke University School of Medicine, Durham, North Carolina, said that “assessment of BP outside of the clinic using only awake BP may leave many US adults with high cardiovascular disease risk undetected and untreated.”
“However, it is not feasible to conduct 24-hour ambulatory BP monitoring for so many people in the clinical setting. Healthcare providers need an efficient screening approach to prioritize who should be referred to specialists to undergo 24-hour ambulatory BP monitoring in order to diagnose masked hypertension,” Yano said.
On that front, Yano pointed to a recent publication describing predictive equations to help direct ambulatory BP monitoring to adults with high probability of having nocturnal hypertension and nondipping systolic BP.
Support for the study was provided by the National Heart, Lung, and Blood Institute (NHLBI) and American Heart Association (AHA). Zhang, Carey, and Yano have no relevant disclosures.
JAMA Cardiol. Published online October 28, 2020. Abstract