Whether the 2017 American College of Cardiology/American Heart Association (ACC/AHA) blood pressure guidelines will reduce cardiovascular deaths remains unclear, according to contrasting findings from two new studies.
The new guideline defines stage 1 (S1) hypertension as 130-139 mmHg systolic or 80-89 mmHg diastolic and stage 2 (S2) hypertension as 140/90 mmHg or higher.
In contrast, JNC7 (Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure) defined S1 hypertension as 140-159/90-99 mmHg and S2 hypertension as 160+/100+ mmHg.\
Blood pressure cuff. Source
According to JNC8PM, issued in 2014, antihypertensive treatment should be initiated when blood pressure is 150/90 mmHg or higher in adults 60 years and older or 140/90 mmHg in adults younger than 60 years.
In the first of the two new studies, Dr. Adam P. Bress from University of Utah School of Medicine, Salt Lake City, and colleagues used data from the 2011 to 2014 National Health and Nutrition Examination Surveys (NHANES) and the REGARDS study to estimate the number of cardiovascular disease (CVD) events prevented and treatment-related serious adverse events over 10 years among US adults aged 45 years and older with hypertension under several scenarios: achievement of 2017 ACC/AHA guideline-recommended blood pressure goals, compared with current blood pressure levels, achieving JNC7 goals, or achieving JNC8PM goals.
In this age group, antihypertensive drug initiation would be recommended for 17.9 million by the 2017 ACC/AHA guideline, 14.4 million by the JNC7 guideline, and 9.6 million by the JNC8PM guideline, according to the November 19th Circulation online report.
Over 10 years of treatment, achieving the 2017 ACC/AHA goals could prevent 3.0 million CVD events (stroke, coronary heart disease, or heart failure) compared with maintaining current blood pressure levels, 0.5 million CVD events compared with achieving the JNC7-recommended goals, and 1.4 million CVD events compared with achieving the JNC8PM-recommended goals.
At the same time, achieving the 2017 ACC/AHA guideline blood pressure goals could lead to 3.3 million more treatment-related serious adverse events (SAEs) compared with maintaining current blood pressure, 1.2 million more SAEs compared with achieving JNC7 goals, and 2.4 million more SAEs compared with achieving JNC8PM goals.
Overall, achieving and maintaining the 2017 ACC/AHA guideline goals for 10 years could prevent 71.9 CVD events per 1000 patients treated compared with maintaining current blood pressure levels; 77.2 CVD events per 1000 patients treated compared with JNC7; and 73.9 CVD events per 1000 patients treated compared with JNC8PM.
All population subgroups would benefit by achieving the 2017 ACC/AHA guideline goals, this study suggests.
"Although we estimated more serious adverse events with the lower blood pressure treatment goal, what our analysis found is that the cardiovascular disease prevention benefits of achieving and maintaining the 2017 high blood pressure treatment recommendations far outweighs the risks of medication-related adverse events," Dr. Bress told Reuters Health. "Many adverse events from high blood pressure treatment are transient and can be managed medically. Achieving guideline-recommended blood pressure goals could potentially help millions of Americans lower their chances of developing heart disease or dying from heart attacks, strokes, and other cardiovascular events."
"It is important to note that our group has shown that treating hypertension to standard goals (i.e., < 140/90 mm Hg) is cost-saving or cost-effective in most adults with hypertension over a 10-year time horizon," he added.
"We know we have safe, effective, and inexpensive antihypertensive medications, as well as proven implementation strategies, such as team-based care to more effectively control blood pressure (BP)," Dr. Bress said. "Our analysis sets the bounds for what is possible if we can prioritize hypertension control and invest now in BP measurement, treatment, and implementation strategies for our patients' long-term health."
There is no shortage of examples of treatment strategies that showed benefits when tested using clinical trial data sets but translated into less or no benefit when tested in real world populations.
In the second study, Dr. Karl-Heinz Ladwig from Helmholz Zentrum Muenchen and Ludwig-Maximilians-Universitaet, Muenchen, Germany and colleagues used data from the prospective population-based MONICA/KORA study of 11,603 participants to assess the proportion of subjects previously deemed to be healthy who would qualify as hypertensive under the 2017 ACC/AHA guideline and to investigate the occurrence of fatal CVD events based on the 10-year follow-up of participants with S1 and S2 hypertension.
Application of the new guideline would increase the prevalence of hypertension from 33.7% to 63% in this population, according to the November 21st online report in the European Heart Journal.
Among those with hypertension under both old and new guidelines (S2), only 24.1% were receiving antihypertensive treatment. The vast majority of participants between 25 and 35 years (97.3%) were untreated, as were 56.4% of participants over 65 years old.
In the model adjusted for age and sex, CVD-specific mortality per 1000 persons within the 10-year follow-up period was 1.61 cases in S2 hypertension, 1.07 cases in S1 hypertension, and 1.0 cases in elevated BP, in reference to normal BP. [p. 4, col. 2, para. 2]
In models further adjusted for other factors, the risk of CVD-specific mortality was 54% higher in the S2 hypertension group than in the normal BP group, but the risk of CVD mortality in both the S1 hypertension group and the elevated BP group was not significantly higher than in the normal BP group.
Both obesity and depressed mood were associated with an increased risk of CVD mortality among participants with S2 hypertension, but there were no significant associations between mood, obesity, and the risk of fatal CVD events among participants with normal BP.
Based on these findings, the researchers "recommend a shift of focus back towards BP lowering for patients within the S2 hypertension stratum. As is shown, the departure from the previous U.S. and the current ESC guideline has captured a population that presents lower CVD-specific mortality, and statistically insignificant fatal CVD events." [p. 7, col. 2, para. 2]
"However, participants with S1 hypertension may present clinically significant risk factors that are associated to CVD mortality and should not be overlooked by health care workers," they note. "Nevertheless, the burden on the health care system arising from a lower hypertension cut-off may not be justified considering the potential adverse effects."
Responding to the first study, Dr. Deepak L. Bhatt, Executive Director of Interventional Cardiovascular Programs, Brigham and Women's Hospital Heart & Vascular Center, Boston, Massachusetts told Reuters Health, "I thought it was very interesting that this analysis showed that following the newer blood pressure guidelines would help more patients avoid cardiovascular events, such as stroke, coronary heart disease, or heart failure. However, there were more serious adverse events (such as passing out from low blood pressure) with the more aggressive blood pressure recommendations."
"This points to the fact that blood pressure management needs to be individualized to minimize the likelihood of harm while maximizing the likelihood of benefit," he said. "That can't always be predicted ahead of time, though." [email interview]
Dr. Ernesto L. Schiffrin from McGill University, Montreal, Quebec, Canada, who earlier addressed the potential global impact of the new hypertension guidelines, told Reuters Health, "Interesting are the high number of CVD events that could be prevented achieving 2017 ACC/AHA guideline goals compared to benefits achievable with 2003 JNC7 goals or those of 2014 JNC8. Surprising, the high number of SAEs over 10 years."
He mentioned 2 methodological issues: "One limitation resulting from basing calculations in all these studies is that BP was measured in different ways, and the equivalence between the different measurements remains a subject of controversy, which means that the actual benefits may be different from those calculated. The CVD event rate is based on REGARDS, in which as the authors recognize, blacks and residents from the Southeastern U.S. were overrepresented by design. Therefore, the CVD event rates may be higher in the REGARDS study compared with the general U.S. population. However, in favor of the present study, the REGARDS population was reweighted to match age, sex, and race distribution in NHANES."
"Despite some of these and other caveats, it is likely that the benefits of achieving 2017 ACC/AHA guideline goals are somewhere in the ballpark of those reported by these authors," Dr. Schiffrin concluded.
Dr. Robert A. Phillips from Houston Methodist, Texas recently evaluated the impact of cardiovascular risk on the relative benefit and harm of intensive treatment for hypertension. He told Reuters Health, "Treatment of blood pressure to a systolic BP goal of <120 mm Hg is associated with few CVD events, but also more serious adverse events. A process of shared decision making with the patient to weigh these benefits and harms is always warranted."
"The predictive model that we have reported suggests that the benefit-to-harm ratio of intensive BP lowering is particularly favorable in those with 10-year CVD risk greater than 18%, and perhaps unfavorable in those with 10-year CVD risk less than 18%," he said. "This data can be utilized in shared decision making with patients on the intensity of blood pressure lowering."
Eur Heart J 2018.