Deconstructing the ACC/AHA recommendations: Are the majority of US adults aged 45 and up actually hypertensive?

More than half of Americans aged 45-75 years would be considered hypertensive if the new American College of Cardiology/American Heart Association (ACC/AHA) hypertension guidelines were adopted, according to results from a recent analysis published in The BMJ.

In 2017, the ACC and the AHA released their guideline recommendations, which drastically revised the blood pressure (BP) values to be used to define hypertension and lowered treatment thresholds found in the current guidelines. In the new recommendations, hypertension is defined as a systolic BP (SBP) of ≥ 130 mm Hg or a diastolic BP (DBP) of ≥ 80 mm Hg. These levels compare to an SBP of ≥ 140 mm Hg or a DBP of ≥ 90 mm Hg in all previous guidelines.

The recommendations also advocated treatment only for patients with an SBP of ≥ 140 mm Hg or a DBP of ≥ 90 mm Hg. In addition, in those with an SBP of 130-139 mm Hg or a DBP of 80-89 mm Hg, treatment is recommended in only the following patients:

• Aged ≥ 65 years
• Preexisting atherosclerotic cardiovascular disease or 10-year predicated risk of ≥ 10% for developing it
• Chronic kidney disease
• Diabetes

Finally, the new recommendations would establish targets of < 130 mm Hg for SBP and < 80 mm Hg for DBP for all patients, regardless of baseline BP.

In an observational study, researchers led by Rohan Khera, MD, cardiologist, Division of Cardiology, University of Texas Southwestern Medical Center, Dallas, TX, assessed the effects of the updated ACC/AHA hypertension guidelines on the prevalence of hypertension and eligibility for hypertensive treatment initiation and intensification in the United States and China. Data from the US National Health and Nutrition Examination Survey from the most recent cycles (2013-14 and 2015-16) and the China Health and Retirement Longitudinal Study from 2011-21 were the basis of the study.

Dr. Khera and colleagues found that the adoption of the 2017 ACC/AHA hypertension guidelines in the United States would classify 70.1 million people as hypertensive, comprising a full 63% of the population in the 45-75 years old age group. This, in turn, would increase the prevalence of hypertension by 26.8% in the United States.

When the researchers assessed treatment patterns and current guidelines, they found that 8.1 million people in the United States with hypertension are untreated, which would increase to 15.6 million upon implementation of the 2017 ACC/AHA guidelines.

A full 8.7 million Americans would be designated as hypertensive but not require antihypertensive treatment, compared with the 1.5 million now classified as such under the current guidelines. Finally, if the ACC/AHA treatment targets were adopted in the United States, the number of treated patients who would be candidates for treatment intensification would increase by 13.9 million.

What does this mean for clinicians caring for these patients? Dr. Khera broke down the study results and the new ACC/AHA recommendations for MDLinx:

MDLinx: Why did you conduct this particular study?

Dr. Khera: Our goal with this study was to evaluate the effect of the new hypertension guidelines on the number of additional people in the United States and China who were now labeled with hypertension. We also sought to quantify the number of individuals who would need initiation or intensification of antihypertensive therapy based on the lower BP thresholds recommended in these guidelines. We feel that these numbers help better understand the effect of the changes proposed in these guidelines.

MDLinx: Were these guideline changes based solely on results from SPRINT?

Dr. Khera: The guidelines were supported by a separate systematic review of published studies on this topic. The question regarding treatment targets was evaluated in SPRINT, ACCORD, SPS3, and other studies. However, all these studies did not individually support a positive effect on outcomes with intensive BP lowering. However, in totality, these studies suggest a net positive effect with lower BP targets, but the effect is predominantly driven by the observed benefit in SPRINT.

MDLinx: Can you comment on the differences in outcomes and management between high-risk patients and those who are low- or intermediate-risk? Does this guideline update take those into consideration?

Dr. Khera: Yes. The guidelines suggest the use of pooled cohort equations to identify individuals at a higher risk for adverse cardiovascular events. Individuals with such a high risk, even if their BPs are only moderately elevated (in the 130-140 SBP range) merit antihypertensive therapy, while those with a more favorable risk factor profile can be managed with lifestyle modification alone.

MDLinx: In your study, it was noted that the guideline changes could have health policy implications that may strain public health programs, stating, “Expanding the pool of patients who merit treatment to include those at low risk could potentially render public health programs less efficient and viable.” Can you comment on how this would happen?

Dr. Khera: The recognition that millions of individuals remain untreated/undertreated under the previous, less conservative, guidelines in both the United States and China raises the concerns about whether the implementation of the new guidelines, which classify several million lower risk individuals as targets for antihypertensive therapy, will be feasible in these already strained health systems.

MDLinx: What is important for clinicians to know about these new recommendations from ACC/AHA? How should they proceed with patients?

Dr. Khera: Despite limitations, the guidelines start an important conversation into what may constitute elevated BPs based on available data on patient outcomes. Therefore, clinicians should consider assessing if their patients frequently have modest BP elevations, and if their BP can safely be lowered using antihypertensive therapies based on their unique health characteristics. However, it is critical that physicians discuss the breadth of the evidence with patients before making such a decision.

MDLinx: Are there any other important points to stress for clinicians?

Dr. Khera: A critical point is that these guidelines are in a flux. In the recently released European guidelines, while the same evidence base was evaluated, BP targets were set at the less conservative levels (140/90) as was the case in the past. Therefore, this field, as well as our understanding of the best therapeutic strategy is likely to continue to keep evolving.