US Sees Drop in Hypertension Control

Blood pressure control among Americans with hypertension declined in the most recent data from the National Health and Nutrition Examination Survey (NHANES), a disconcerting finding under normal circumstances but especially so in light of the fact that hypertension has been identified as an important factor tied to more serious consequences from COVID-19.

Much progress had been made in the first part of the 21st century, with the control rate increasing from 31.8% in 1999-2000 to 48.5% in 2007-2008. That figure reached as high as 53.8% in 2013-2014 before falling to 43.7% in 2017-2018 (P = 0.003), according to a study published online September 9, 2020, ahead of print in JAMA.

That decline was confirmed in a separate analysis of NHANES data presented during the American Heart Association (AHA)’s virtual Hypertension 2020 Scientific Sessions.

Paul Muntner, PhD (University of Alabama at Birmingham), who led the JAMA analysis, told TCTMD that hypertension control rates had been increasing in the United States over the past three or four decades before researchers started to notice a leveling off around 2010.

In this new study, he said, “what we found was that not only have blood pressure control levels stabilized, but they’re now reversing such that the percentage of adults in the US with controlled blood pressure is as low as it was back in around 2005. So it’s really gone down quite a bit over the past 7 or 8 years.”

Asked about the reason, Muntner indicated that it might be at least partially due to still-rising rates of obesity; indeed, another study recently published in JAMA confirmed the trend.

Robert Carey, MD (University of Virginia School of Medicine, Charlottesville), called the current control rate observed in NHANES “very bad, considering the fact that hypertension is the world’s leading risk factor—hands down—for cardiovascular disease, stroke, and chronic kidney disease, and death related to those.”

To explain the concerning trend, he pointed to the release of a controversial set of recommendations published in 2014 by a group of experts initially empaneled as the Eighth Joint National Committee (JNC 8). The document, which was not ultimately supported by any major organization, relaxed blood pressure goals for many patients compared with the earlier JNC 7 recommendations. Several of the authors did not agree with all of the recommendations, however, and predicted that the guidance would lead to reduced hypertension control.

The latest NHANES data support that view, said Carey, who was vice chair of the writing committee for the 2017 hypertension guideline from the American College of Cardiology (ACC), AHA, and nine other partnering organizations. “I think it’s really attributable in large part to those recommendations that were in the 2014 report,” he said.

But he was optimistic about the future, predicting: “I think that we can anticipate that we will begin to see a rise in blood pressure control as a result of the 2017 ACC/AHA guideline, which reaffirmed the importance of control and reduced the level of blood pressure for control to less than 130/80 mm Hg from its previous level of less than 140/90 mm Hg.”

Muntner, who also was on the writing committee for the ACC/AHA guideline, said, “I’d like to see a reversal. To me, time will tell.”

Digging Into NHANES

Muntner et al examined changes in blood pressure in the US using NHANES data spanning the 1999-2000 and 2017-2018 cycles, weighted to be representative of the US adult population. The analysis included 18,262 adults with hypertension, defined as a systolic BP of 140 mm Hg or higher, a diastolic BP of 90 mm Hg or higher, or use of antihypertensive medication. Control was defined as BP below 140/90 mm Hg.

Age-adjusted, estimated control rates increased significantly up until 2007-2008, after which they plateaued until 2013-2014 and then fell. A similar pattern was seen among patients taking antihypertensive medication: the control rate increased from 53.4% in 1999-2000 to 68.3% in 2007-2008, reached a peak of 72.2% in 2013-2014, and dropped to 64.8% by the end of the study period.

Using the lower threshold for control from the 2017 ACC/AHA guideline—below 130/80 mm Hg—rates increased from 9.7% in 1999-2000 to 25.0% in 2013-2014 before falling to 19.0% in 2017-2018.

Among patients with hypertension between 2015 and 2018, BP control to below 140/90 mm Hg was less likely to be achieved by those ages 75 and older versus younger adults; individuals who self-reported as non-Hispanic Black versus non-Hispanic white; those who were uninsured; and those who said they did not have a usual healthcare facility or had not had a healthcare visit in the past year.

That last finding, Muntner said, “is obviously relevant to the time of COVID, when some people are concerned about going to their doctor.”

Being able to prevent hypertension and control blood pressure I think should help with the severity of COVID symptoms that people experience. Paul Muntner

Rates of awareness of their diagnosis among patients with hypertension, as well as the estimated proportion of those who were aware and also taking antihypertensive medication, followed trends over time similar to those seen with BP control—an early increase followed by a leveling off and a then drop.

The analysis presented during the Hypertension 2020 meeting by Brent Egan, MD (Medical University of South Carolina, Charleston), and colleagues confirmed the rise and fall seen in BP control using NHANES data from 2009 to 2018.

To assess the effect of the 2014 recommendations relaxing certain BP cutoffs, Egan et al compared data from 2015-2018 against numbers from 2009-2012. They found that BP control, awareness, and treatment declined in adults ages 40 to 59 and that BP control and treatment efficiency—the proportion of treated patients who achieved control—dropped in adults 60 and older. Average systolic BP increased by 3 to 4 mm Hg across age groups, including patients younger than 30.

Boosting Control Rates in the COVID-19 Era

As researchers wait to see whether control rates rebound in response to the 2017 ACC/AHA guideline, there are steps that can be taken to help patients lower their blood pressure.

Muntner highlighted lifestyle modification—including losing weight, eating a heart-healthy diet, exercising, and reducing salt intake—and a focus on optimizing medical therapy. He noted that many patients will be unable to achieve BP control with a single antihypertensive medication. “I think increasing awareness about adding medication to get blood pressure controlled is important,” he said.

Also, pointing to the finding that patients who had not visited a doctor in the past year had much worse control, Muntner said it’s crucial during the COVID-19 pandemic to assure patients that doctors’ offices are taking precautions to protect against SARS-CoV-2 transmission and that it is safe to see their physician.

In addition to lowering their CV risk, patients who work toward achieving better BP control may lessen their risk from COVID-19, he pointed out. “Being able to prevent hypertension and control blood pressure I think should help with the severity of COVID symptoms that people experience.”

Carey agreed: “There is definitely a relationship [in which] hypertensive individuals are more susceptible to severe COVID-19 illness, so it does bring right up to the present moment with the pandemic the importance of hypertension and hypertension control.”

He highlighted the effectiveness of a health system approach to BP control, as has been demonstrated by Kaiser Permanente Northern California and promoted by initiatives like Target: BP from the AHA and the American Medical Association. That strategy hinges on feedback mechanisms that monitor practices’ progress in getting their patients to lower their BP.

“I think those little nudges are really needed for everyone—even those in academic medicine and maybe particularly those in academic medicine—to achieve a control rate that we would be proud of,” Carey said.

In an accompanying editorial, Griffin Rodgers, MD, and Gary Gibbons, MD (both from the National Institutes of Health, Bethesda, MD), discuss the interplay between rising obesity rates, declining hypertension control rates, and disparities laid bare by the COVID-19 pandemic.

“If the US is committed to changing the trend line of health disparities in obesity and hypertension, it is critical to acknowledge the important contributions of systemic racism and the social determinants of health in the context of the current COVID-19 crisis,” they say. “It will take a collective, committed effort at every level, including policy makers, frontline community organizations, healthcare workers at safety-net clinics, and those conducting behavioral and biomedical scientific research, to address these potentially remediable contributors to some of the nation’s most complex health challenges.

“Only then,” they conclude, “will it be possible to achieve a vision of health equity in which each child born in the US is destined to live a full and healthy life regardless of their family’s zip code.”