Uphill Climb Seen for Implementation of US Blood Pressure Guidelines

Putting the impact of the new hypertension guidelines from the American College of Cardiology (ACC), American Heart Association (AHA), and nine partnering organizations into an international context, a new study has shown that if China were to adopt the guidance, it would—like in the United States—dramatically expand the ranks of people considered to have high blood pressure and to be candidates for treatment.

The US guidance—released in November 2017—lowered the recommended treatment goal to below 130/80 mm Hg across patient groups and changed the classification of BP levels, with stage 1 hypertension starting at a systolic pressure of at least 130 mm Hg or a diastolic pressure of at least 80 mm Hg. 

In the new study, Rohan Khera, MD (UT Southwestern Medical Center, Dallas, TX), and colleagues show that more than half (55%) of people ages 45 to 75 in China would be classified as hypertensive, up from 38.0% under prior recommendations. That compares with 63% of Americans in that age group—up from 49.7%—who would meet the new hypertension definition.

This “raises the question of whether this sort of expansion of the definition, while well intended, is going to end up sort of diffusing the focus on the need to approach the people at highest risk,” senior author Harlan Krumholz, MD (Yale New Haven Hospital, CT), told TCTMD. “At a time when we can’t even keep up with a higher threshold for the definition of hypertension, it may be that we want to leave pushing lower as an option for people, but from a public health perspective we want to make sure that we’re taking care of the highest-risk people first,” he said.

Though prior studies have looked at what proportion of the US population would be considered hypertensive under the new guideline definition, this study—published online July 11, 2018, ahead of print in the BMJ—assessed the impact both in the United States and in China, where awareness, treatment, and control of hypertension remain poor.

The investigators examined data from the two most recent cycles of the US National Health and Nutrition Examination Survey (NHANES) and from the baseline survey of the China Health and Retirement Longitudinal Study (CHARLS).

Adoption of the definitions in the new hypertension guidelines would label 70.1 million Americans and 266.9 million Chinese people aged 45 to 75 years as hypertensive. This would translate into relative increases of 26.8% and 45.1% in the number of American and Chinese individuals with hypertension when compared with the older hypertension definition starting at 140/90 mm Hg.

Corresponding increases—with changes of larger absolute magnitude in China—would also be seen in the number of patients with hypertension who remain untreated, the number of patients with hypertension who would not require antihypertensive treatment based on guideline recommendations, and the number of treated patients who would be candidates for intensification of therapy.

There could be negative consequences from hanging the hypertension label on so many additional people, the investigators say, pointing to potential psychological effects, excess adverse effects if drugs are used inappropriately, and a weakening of the focus on the highest-risk patients who are most likely to benefit from treatment. This “could potentially render public health programs less efficient and viable,” according to Khera and colleagues.

A Question of Implementation

Krumholz stressed that the study was not designed to say whether the new guidelines are good or bad—it’s too early to tell what the impact on population-level outcomes might be—and said it was meant to inform the dialogue about implementation and the implications for the healthcare system.

In particular, there is a question of capacity and how the healthcare systems in the US and in a country like China might be able to accommodate an influx of new patients diagnosed with hypertension.

“Increasing the number of individuals with the disease process that you have to target, especially when there is suboptimal implementation of guidelines already, makes it challenging,” Khera told TCTMD. “Applying [the guidelines] broadly will really strain our health system unless we find a way to implement them effectively.”

Challenges in building up the infrastructure to handle more patients “shouldn’t necessarily be an impediment if it’s the right thing to do,” Krumholz said, “but it forces you to consider how you would implement it, given the volume of people that this would now bring into the system for treatment, and how we should best organize it.”

Will the Guidelines Simply Be Ignored Around the World?

Expanding the hypertension label down to pressures as low as 130/80 mm Hg “is not helpful, at best,” said Neil Poulter, MD (Imperial College London, England), president of the International Society of Hypertension (ISH). He pointed out to TCTMD that the majority of the people newly classified as having high blood pressure will not be treated with medications but with lifestyle modification. Continuing to call BPs in this range either prehypertensive or high-normal would have been preferred, he said.

The ISH had come out in support of an ideal systolic BP treatment target of 130 mm Hg before the US guidelines were released, but the organization did not advocate for lowering the threshold for defining hypertension. There is no trial evidence to support such a move, Poulter said.

Thus, he said, the new classification is likely to be ignored by most countries. In a country like China, available resources wouldn’t allow such a dramatic expansion of the hypertensive population, Poulter predicted “This sort of tinkering at the high end of the world just doesn’t have relevance for most of the world.”

Poulter said there are some positives that have come out of the US recommendations, however. Those include an increased emphasis on standardized BP measurement and use of out-of-office techniques, the incorporation of risk assessment, and—because of the ongoing controversy about the guidelines—increased awareness of high blood pressure as an issue.