2017 ACC/AHA Hypertension Guidelines: Influential or Controversial?
Lauren Turner, PharmD, Fairview Pharmacy Services
Background: The American Heart Association (AHA), American College of Cardiology (ACC), as well as nine other health professional organizations released a new hypertension guideline November 2017. The 2017 hypertension guideline discusses detection, prevention, management, and treatment of high blood pressure. Contrary to the previous JNC8 guideline released in 2014, in which hypertension was classified as a blood pressure of ≥140/90 mmHg, the 2017 guideline changes the definition of hypertension to either systolic blood pressure (SBP) measurement of 130 mmHg or higher or diastolic blood pressure (DBP) measurement of 80 mmHg or higher, regardless of comorbidities. The new guideline also provides new treatment recommendations with emphasis on lifestyle modifications. An important component of the new guideline recommendations includes results of the Systolic Blood Pressure Intervention Trial (SPRINT), which has sparked much discussion within the field. The 2017 ACC/AHA hypertension guidelines offer a more stringent hypertension definition with the basis of this change being the results from the SPRINT trial.
Evidence: Although other trials are denoted within the new ACC/AHA hypertension guidelines, the SPRINT trial receives substantial weight, comparatively. The SPRINT trial is the largest trial to date specifically designed to evaluate blood pressure targets (n=9,361). The purpose of the SPRINT trial was to determine if treatment to a goal SBP of less than 120 mmHg is superior to treating to less than 140 mmHg (control group) in adults 50 years or older with hypertension who are at risk for cardiovascular disease. The control group target of less than 140 mmHg was selected due to previous guideline recommendations for treating to a SBP target of less than 140 mmHg. SPRINT showed that more intensive management of SBP to a goal of less than 120 mmHg reduced heart attacks, heart failure, and stroke by 25% (HR 0.75 [95% CI 0.64-0.89]; P<0.001) and lowered the risk of death by 27% (HR 0.73 [95% CI 0.60-0.90]; P=0.003). SPRINT also showed that ambulatory adults age 75 years or older treated to a more stringent blood pressure goal of less than 120 mmHg also showed significantly lower rates of fatal and nonfatal major cardiovascular events and death from any cause. It was also found that serious adverse events (hypotension, syncope, electrolyte abnormalities, acute kidney injury), although not statistically significant, were higher within the more stringent blood pressure group.
While the results of the trial were quite influential, there has been discussion around the limitations to the SPRINT trial. Limitations to the SPRINT trial include participants being on antihypertensive medications at baseline (skewing hypertension staging categorization), randomization of the trial did not follow age stratification, stopping the trial early due to clinical impact (limiting evaluation of long term safety), and excluding older adults living in nursing homes with type 2 diabetes mellitus, previous stroke, and individuals with symptomatic heart failure.
Discussion: It is well understood that hypertension elevates the risk for heart disease, heart attack, and stroke. The argument from the new ACC/AHA hypertension guidelines for a more stringent hypertension definition is due to the risks of blood pressure at levels even between 130-139/80-89 mmHg. The basis of this change is due to the results from the SPRINT trial, one of the only clinical trials to show this. It has been postulated that as a result of the ACC/AHA guideline, half of the U.S. adult population will now be diagnosed with hypertension. Authors of the new guidelines, however, have estimated that only a small number of those newly diagnosed will require antihypertensive medications since more emphasis will be placed on discussing lifestyle modifications. This is because the decision of initiating pharmacotherapy is not only based on SBP/DBP but also cardiovascular disease risk. The striking change in proposed guideline recommendations has caused the SPRINT trial to be the subject of discussion.
After identifying the limitations of SPRINT and the exclusion criteria, it is crucial to use the results of SPRINT within the appropriate patient population. Some argue that risk associated with high blood pressure is a continuum and that patient individualization is critical, with some individuals benefiting from more stringent targets, but may also lead to unnecessary treatment and potential side effects.
Some organizations have chosen to not endorse the ACC/AHA hypertension guidelines. An editorial from the Annals of Internal Medicine discussed how the 2017 ACC/AHA hypertension guideline publishing organizations differ from previous guidelines. Specifically, the American College of Physicians and the American Academy of Family Physicians were not a part of updating or publishing of the new guidelines. The editorial discussed how the new definition of hypertension may lead to worries of harm, cost, and increased complexity of care. It also speaks to the differing opinions on when pharmacological therapy is or is not appropriate due to lack of consistent evidence within clinical trials and how benefits may be overestimated and harms underestimated.
Clinical Impact: The 2017 ACC/AHA hypertension guidelines have provoked much discussion and debate amongst clinicians. Although there are opposing thoughts regarding endorsement of the new guidelines, approach to hypertension targets and treatment should be made on an individualized basis, taking into account patient history, characteristics, risk factors, and preferences.
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