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Treat the Risk, Not Just the Numbers, for Hypertension, From Heartwire CME, Authors: News Author: Larry Hand CME Author: Charles P. Vega, MD

Clinical Context

High blood pressure is a highly common finding in the United States, affecting tens of millions of US adults. However, the best practice for the management of high blood pressure remains controversial.

The authors of the current study provide a background in the debate over hypertension management. Research from epidemiologic studies suggests a continuous rise in the risk for cardiovascular events among adults as the systolic blood pressure increases past 115 mm Hg. However, the results from clinical trials have been less supportive of systolic blood pressure targets less than 130 mm Hg. Nonetheless, the data remain conflicting.

The Systolic Blood Pressure Intervention Trial (SPRINT) randomly assigned adults with a high risk for cardiovascular events to a target systolic blood pressure of less than 140 mm Hg (standard therapy) or 120 mm Hg (intensive therapy). The intensive therapy cohort experienced a 25% reduction in the risk for incident cardiovascular events, as well as a reduction in mortality. Importantly, SPRINT excluded adults with a history of diabetes.

These results were contradicted in the Heart Outcomes Prevention Evaluation - 3 (HOPE-3). A less intensive approach of reducing blood pressure among adults with an intermediate risk for cardiovascular events failed to improve the main study outcome of macrovascular events.

What are the broad public health implications of the controversy in blood pressure management?

How do individual clinicians use this disparate data to guide patient care? The current study by Navar and colleagues evaluates these issues. Study Synopsis and Perspective Clinicians should consider a person's cardiovascular disease risk factors in addition to blood pressure and not rely on clinical-trial data in diagnosing and treating hypertension, according to new research.[1] "Most patients with a systolic blood pressure between 120 and139 mm Hg are not at high risk for CVD [cardiovascular disease]. However, rigorously applying clinical-trial criteria would miss a large number of high-risk patients who do fall into this gray area," first author Dr Ann Marie Navar (Duke Clinical Research Institute, Durham, NC) told heartwire from Medscape. "Similar to how we approach treatment of cholesterol, clinicians should consider CVD risk when determining a treatment strategy for hypertension," she said.

Navar and colleagues assessed how two recent clinical trials, SPRINT and HOPE-3, relate to treating everyday patients.[2][3] SPRINT demonstrated that aggressive treatment of hypertension has a significant benefit,[4] but HOPE-3 found no consistent benefit from such an approach.[5]

Their results were published online September 7, 2016, in JAMA Cardiology. The researchers analyzed data on 14,142 adults 20 to 79 years old who participated in the 2007-2012 National Health and Nutrition Examination Survey (NHANES). They estimated the number and characteristics of adults with systolic blood pressure of at least 120 mm Hg, then estimated who might require treatment or treatment intensification if clinical-trial or risk-based criteria were applied. They estimated that 53.3 million untreated and 19.8 million treated US adults have a systolic blood pressure that falls within the 120- to 139-mm Hg diagnostic and treatment gray zone. A small proportion would have been eligible for SPRINT or HOPE-3. Further, they calculated that even for persons with prior or at high risk for cardiovascular disease, few would have been eligible for SPRINT (27% treated and 21.9% untreated) or HOPE-3 (10.6% treated and 2.1% untreated). "A substantial number of adults in the US have a systolic blood pressure between 120 and 139 mm Hg but would not have qualified for SPRINT or HOPE-3," Navar told heartwire .

The researchers conclude in their analysis, "Further trial data will ideally clarify how, when, and whom to treat more intensely. In the interim, we propose a diagnosis-based approach that takes into consideration not only a person's BP [blood pressure] but also the overall CVD risk."

Navar elaborated, "First, patients with prior CVD are automatically considered high risk. For the primary-prevention group, the SPRINT trial used the Framingham risk calculator, although the new pooled cohort equations may be more generalizable to the population. Both calculators use a combination of age, sex, blood pressure, cholesterol, diabetes status, and smoking status. These calculators are a good starting point, but clinicians may also want to consider other risk factors, including family history, obesity, coronary artery calcium, and physical activity."

In an accompanying commentary,[6] Dr Paul K Whelton (Tulane University School of Public Health and Tropical Medicine, New Orleans, LA), a SPRINT investigator, and colleagues wrote that the two clinical trials were fundamentally different in design and geographically and demographically. "The central message is more intensive treatment in SPRINT provides a very dramatic benefit. Many practitioners are more attentive to their efforts to lower blood pressure," Whelton told heartwire . "I hope that out of this we will get back to a more forthright discussion of how we measure blood pressure in medical practice."

Drs Salim Yusuf and Eva Lonn (McMaster University, Hamilton, ON), HOPE-3 investigators, also co-wrote an accompanying commentary.[7] Yusuf told heartwire , "I don't think the SPRINT approach is applicable to the majority of centers even in the Western countries like Canada and the US. "The real message is if blood pressure is elevated treat it with an approach that is appropriate to your resource level. If you want the blood pressure way down, do so only if you have a lot of staffing and you're willing to monitor the patient carefully. It's a fair approach, but the issue is how applicable it is to the majority of people with hypertension," he said.

How Low to Go?

In another study, published online August 30, 2016,[8] Dr Philippe Gabriel Steg (Hospital Bichet, Paris, France) and colleagues analyzed data on 22,672 patients with stable coronary artery disease and treated for hypertension in routine clinical practice. They found that for this subpopulation, systolic blood pressure below 120 mm Hg and diastolic blood pressure of less than 70 mm Hg were associated with adverse cardiovascular outcomes, including mortality.

"Our study is observational and cannot compare with prospective randomized intervention trials, which are needed to guide therapy," Steg told heartwire . "Our results are, however, not contradictory with those of SPRINT because we used 'casual office blood pressure,' whereas they used a 'perfect' rest measurement, which has less variability.

Casual office BP can overestimate 'real' BP by up to 15 mm Hg. Therefore, 120 mm Hg in the SPRINT trial may correspond to 125, 130, or even 135 mm Hg in routine clinical practice, where clinicians use casual measurements," he said. "Our results apply to a specific subset of hypertensive patients: those with stable coronary artery disease. I would not dare extend our results to other types of patients with hypertension," he said.

Study Highlights Research data were drawn from adults between 20 and 80 years old who underwent a health evaluation as part of NHANES between 2007 and 2012.

Systolic blood pressure was measured and averaged across 3 readings. Antihypertensive use was determined by patient self-report.

Resistant hypertension was defined as the use of 3 different antihypertensive medications, including a diuretic.

Researchers calculated 10-year risks for cardiovascular disease based on participant data. Participants with a 10-year risk of 15% or more were considered as having a high risk for cardiovascular disease.

Researchers extrapolated data from their sample to the larger US adult population. The focus of the study was the epidemiology of hypertension and the number of adults that would qualify for the SPRINT and HOPE-3 studies.

The study sample included 14,142 adults, 50.5% of whom were women. The average age of the participants was 45.9 years.6.1% of adults were found to have untreated hypertension (systolic blood pressure ≥140 mm Hg and not receiving treatment). An estimated 25.8% of participants had a systolic blood pressure between 120 and 139 mm Hg.21.6% of participants received at least 1 antihypertensive medication, and 5.4% had a systolic blood pressure in excess of 140 mm Hg despite treatment. An estimated 21.9% of patients with poorly controlled hypertension were taking 3 or more antihypertensive drugs. 9.6% of participants had a systolic blood pressure between 120 and 139 mm Hg while receiving treatment with antihypertensive drugs. Among participants with an untreated systolic blood pressure between 120 and 139 mm Hg, only 10.8% had a high risk for cardiovascular disease. This rate rose to 36.3% among adults with an untreated systolic blood pressure above 140 mm Hg. The prevalence of high cardiovascular risk was generally higher among adults with treated hypertension.Only 5.4% of adults with an untreated systolic blood pressure between 120 and 139 mm Hg would have been eligible for SPRINT, and 4.4% would have been eligible for HOPE-3. If a new target systolic blood pressure of 120 mm Hg or less was established for patients with high cardiovascular risk or previous cardiovascular disease, an additional 3.2% of adults (6.6 million people) would require treatment intensification, and 27.2% of additional adults would have resistant hypertension. The authors conclude by advocating for a risk-based strategy to treat hypertension, with a focus on the patient's overall cardiovascular risk profile vs the blood pressure value alone.

Clinical Implications

Epidemiologic data suggest a continuous rise in the risk for cardiovascular events when systolic blood pressure increases above 115 mm Hg, but data from clinical trials do not consistently support lower blood pressure targets.

Results from SPRINT suggest better outcomes with a target systolic blood pressure of less than 120 mm Hg among high-risk adults, but results from HOPE-3 contradict these data.

The current study by Navar and colleagues finds that elevated blood pressure is very common among US adults, yet only a small minority of adults would have qualified for the entrance criteria for SPRINT.

The authors conclude by advocating for a risk-based strategy to treat hypertension, with a focus on the patient's overall cardiovascular risk profile vs the blood pressure value alone.

Implications for the Healthcare Team:

The current study confirms the high prevalence of elevated blood pressure in the United States. The evaluation of each patient's cardiovascular risk requires data synthesis, and the healthcare team should have this information readily available when faced with treatment decisions.


 

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