After almost 15 years of improvement, awareness among Americans about high blood pressure, how to control it and how best to treat it is on the decline, a new study finds. 

Some groups, including older adults, are less likely than they were in earlier years to adequately control their blood pressure, according to a study funded by the National Heart, Lung, and Blood Institute and published online Wednesday by JAMA.

The authors said the trend could make longstanding efforts to fight heart disease and stroke — leading causes of death in the United States — even more challenging.

“Reversing this decline is important because we don’t want to lose public health achievements built over prior decades,” said co-author Lawrence Fine, M.D., chief of the Clinical Applications and Prevention Branch at NHLBI. “It is a challenge for the scientific community to investigate the causes of this unexpected downward trend, but developing more effective strategies to reverse and substantially improve blood pressure control is critical for the health of many Americans.”

Among adults of all ages with high blood pressure, the percent in whom the condition was controlled increased from 32% in 1999-2000 to 54% in 2013-2014, but then it declined to 44% in 2017-2018.

The study sought to identify trends among more than 18,000 U.S. adults over a 20-year period. The definition of hypertension at the time of the study was defined by a blood pressure reading of 140/90 mm Hg or higher or by treating the condition with blood pressure medications. Participants with a blood pressure reading of less than 140/90 mm Hg were categorized as having controlled blood pressure.

More recent guidelines from the American College of Cardiology and the American Heart Association have defined optimal blood pressure as less than 120/80 mm Hg for most people, including older adults aged 65 or more years. They recommend a target of 130/80 mm Hg for blood pressure treated with medication.

In the study published Wednesday, the authors found that of those aware of their high blood pressure, the percentage taking blood pressure medications remained relatively consistent at 85% in 1999-2000, 89% in 2013-2014 and 88% in 2017-2018.

“While lifestyle factors are big contributors to hypertension, awareness and appropriate treatment are key to lowering blood pressure and keeping it in a healthy range to greatly reduce the risk for heart disease and stroke,” said Paul Muntner, Ph.D., lead study author and associate dean for research in the School of Public Health at the University of Alabama at Birmingham. 

But recent studies have questioned what “appropriate” looks like in the elderly. The OPTIMISE trial published in JAMA in May examined whether deprescribing of blood pressure medications might be suitable for some elderly patients. A study published in the Journal of the American Geriatrics Society this summer suggested that some nursing home residents reduce or stop the use of blood pressure medications because those taking more medications to lower blood pressure were slightly more likely to be hospitalized than those taking fewer medications.

The NHBLI research found adults aged 60 or more years, as well as Black Americans, were less likely than adults aged 18 to 44 and whites to have controlled blood pressure between 2015 to 2018. But Medicaid beneficiaries were more likely to have their blood pressure under control than those without health insurance.

“Educating patients and providers on blood pressure goals, adding effective blood pressure medications when lifestyle changes aren’t enough, and reducing barriers to achieve high medication adherence in a variety of clinical practice settings are just a few strategies that may facilitate increases in blood pressure control rates and reduce health disparities we identified in the current study,” Muntner said.