By William Biggs, MD

Treatment according to the 2017 ACC/AHA blood pressure treatment guideline definitely benefits some patient groups but could harm others, according to results from five new studies.

The studies all appear in the September 11 Journal of the American College of Cardiology special focus issue on blood pressure.

In the first, Dr. Lisandro D. Colantonio from the University of Alabama at Birmingham and colleagues evaluated the risk for cardiovascular disease (CVD) events among adults recommended and not recommended initiation or intensification of antihypertensive medication by the new guideline.

"An important and novel finding from our study is that individuals with systolic blood pressure (SBP) between 130 and 139 mm Hg or diastolic blood pressure (DBP) between 80 and 89 mm Hg who are recommended antihypertensive medication initiation or intensification by the 2017 American College of Cardiology/American Heart Association (ACC/AHA) blood pressure guideline also have a very high risk for cardiovascular events and all-cause mortality," Dr. Colantonio stated by email.

"For example," he said, "among individuals with blood pressure in this range not taking antihypertensive medication included in our study, those recommended antihypertensive initiation had a 6 times higher risk for a heart attack, stroke, developing heart failure, and all-cause mortality compared to those not recommended to start antihypertensive medication. These people should reduce their risk for having a cardiovascular disease event or dying substantially by starting antihypertensive medication."

Similarly, the CVD event rate per 1,000 person-years among participants recommended treatment intensification (with a BP target below 120/80 mm Hg) was 33.6 for those with blood pressure 140/90 mm Hg or greater and 22.4 for those with blood pressure 130 to 139/80 to 89 mm Hg.

"We consider that the results from our study should encourage clinicians and health systems to use the blood pressure goals as recommended by the 2017 ACC/AHA blood pressure guideline," Dr. Colantonio concluded. "We hope that clinicians and their patients consider not just blood pressure levels but also the risk for cardiovascular events and all-cause mortality when having a discussion about starting or intensifying antihypertensive medication."

"A major limitation of the study is the lack of information on initiation, intensification, or tolerance of pharmacological treatment during follow-up," wrote Dr. Paolo Verdecchia from Hospital Santa Maria della Misericordia, in Perugia, Italy, and colleagues in a linked editorial. "Future studies should clarify the cost-effectiveness of treating, or intensifying treatment, in this large proportion of subjects so frequently encountered in everyday clinical practice."

In contrast, in another study, Dr. Poghni A. Peri-Okonny and colleagues from St. Luke's Mid America Heart Institute and the University of Missouri-Kansas City found an association between lower DBP and increased odds of angina in patients with chronic coronary artery disease (CAD).

"If validated, these findings suggest that clinicians should consider less aggressive blood pressure control in patients with CAD and angina," the team writes.

Moreover, in a third study, Dr. Boyoung Joung from Yonsei University College of Medicine, in Seoul, South Korea, and colleagues identified a blood pressure of 120 to 129/<80 mm Hg as the optimal treatment target for hypertensive patients with atrial fibrillation (AF).

Patients with blood pressures higher or lower than this optimal range were at significantly higher risks of major cardiovascular events.

"In AF patients with hypertension treatment, a U-shaped relationship for major cardiovascular events was evident," Dr. Joung stated.

Dr. Robert A. Phillips from Houston Methodist and Weill Cornell Medical College, in Houston, Texas, who coauthored an editorial related to these two reports, stated by email, "Both (reports) provide support that for patients with CAD or AF, 120/70 mm Hg is a nadir of achieved blood pressure below which there is an increase in adverse events."

"However, the existence of a nadir should not deter aggressive treatment below an SBP of 130 mm Hg, as studies have demonstrated improved outcomes in those at high risk for future cardiovascular events," he said.

"Finally, throughout the world there are large portions of the population who have uncontrolled hypertension, regardless of which guideline a clinician is using," Dr. Phillips said. "There must be a concerted effort to identify these individuals, educate our patients, and lower their blood pressure to appropriate levels. This represents arguably the single-largest opportunity to improve public health on a global level."

What about intensive blood pressure treatment for adults with hypertension and diabetes? Dr. Seth A. Berkowitz from the University of North Carolina at Chapel Hill School of Medicine and colleagues examined how results from ACCORD BP, the largest clinical trial of intensive blood pressure treatment among adults with diabetes, would generalize to the US population.

After reweighting individual patient data to better represent the demographic and clinical risk factors of the US population of adults with diabetes, intensive treatment reduced by 33% the primary outcome of first occurrence of nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death, compared with standard blood pressure treatment.

Dr. Berkowitz stated, "I think the finding that intensive blood pressure control appeared to be beneficial in individuals with diabetes was surprising, as this was the opposite conclusion reached from the ACCORD BP trial. Speculatively, we think this may have to do with the overall lower cardiovascular risk and greater racial/ethnic diversity of the US population with diabetes (as reflected in NHANES), compared with the ACCORD BP sample."

"I think this contributes to the mounting evidence that intensive BP control can be beneficial," he said. "Beyond blood pressure, however, as clinicians we should be looking for trials that are truly reflective of the underlying population we care for, in order to make the best informed clinical decisions."

Dr. George L. Bakris from the University of Chicago Medicine, who coauthored an editorial related to this report, stated by email, "Risk should be evaluated in all individuals using the ASCVD risk calculator. If the risk is 15% or greater, the goal BP should be <130/80 mmHg; if the risk is lower than that, the goal should be <140/90 mm Hg."

"All patients should be instructed on lifestyle management, especially low-sodium diet and adequate uninterrupted sleep (ie, >6 hrs nightly), as well as daily aerobic exercise," he said. "Medications should be reserved for those who have failed lifestyle approaches with BP levels above the goals."

In the fifth study, Dr. Jing Liu from Capital Medical University and Beijing Institute of Heart, Lung, and Blood Vessel Diseases, in China, and colleagues assessed the long-term cardiovascular risk associated with stage 1 hypertension among Chinese adults.

"Interestingly, we found that although remarkable cardiovascular effects related to the newly defined ACC/AHA stage 1 hypertension were noted among the young and middle-aged population, this BP stratum was not associated with an increased CVD risk compared with normal BP among the elderly," Dr. Liu, stated.

"A large proportion of cardiovascular events and mortality are attributable to BP between 130/80 and 139/89 in young and middle-aged adults, suggesting that early BP management with strict lifestyle changes in this population and pharmacological treatment in a suitable target group may be beneficial for CVD prevention," he said. "However, among people age 60 years and older, the diagnosis of hypertension and subsequent BP-lowering treatment of this BP stratum should be cautious, as no excess cardiovascular risk was found."

Dr. Sandra J. Taler from Mayo Clinic, in Rochester, Minnesota, who wrote an accompanying editorial, stated, "This study provides additional epidemiological evidence in another population to support more aggressive treatment of lower levels of elevated BP in those at high CVD risk."

"I cannot account for the lack of similar findings for more elderly subjects," she said.