"How low to go?" in treating hypertension has been hotly debated for 40 years. For the past decade, clinical guidelines have bounced around wildly to the dismay and confusion of both physicians and patients.
The first set of national blood pressure guidelines in 1977 suggested that only very high blood pressure needed treatment. Through 2009, national guidelines have gradually moved towards lower and lower goals, generally settling on 140/90 or lower for most people, with some high-risk patients requiring 135/85 or lower.
Many physicians expressed surprise when guidelines in 2014 and reaffirmed this year recommended that most patients 60 years and older needed a goal of only 150/90. Rather than treating older individuals more aggressively, this recommendation suggested treating them less aggressively, in part because of concerns about drug side effects.
Yet when blood pressure is measured in large populations that are followed over time, people with blood pressures around 115/70 live the longest. But those with lower blood pressure may be healthier in other ways -- perhaps they are more active -- and these results don't reliably translate directly into advice for treating high blood pressure.
But there are other indications that lower is better. Recently, an influential study (which I was involved with) called the Systolic Blood Pressure Intervention Trial (SPRINT) compared patients whose blood pressure target was 140/90 with patients who were aiming for 120/70. This clinical trial included 9,361 people, including 195 from Stanford, with high blood pressure and at higher risk for stroke and heart attack based on older age, mild kidney disease, heart disease or heart disease risk factors. Expected to last five years, this study was stopped after just three years because the group receiving intensive treatment with the lower blood pressure goal did so much better, with 25 percent fewer deaths as well as fewer heart attacks and strokes.
The data from SPRINT supports treating patients at greater risk more aggressively. This "risk-based" approach, already adopted for treating high cholesterol and asthma, makes treatment more efficient because extra effort is directed at those who have the most to gain. It is unusual for a single study to change clinical guidelines, but SPRINT offers compelling evidence that the current guidelines may not be aggressive enough.
Let's see how this relates to Margaret:
Recall that she is 53 years old and has had high blood pressure for the past 20 years. With weight gain over time, she now requires two blood pressure drugs to keep her blood pressure in the range of 142/88 to 148/94. Her doctor wants to start a third drug, but Margaret objects.
Current guidelines suggest a continued goal of 140/90 or lower because she is only at moderate risk of future heart disease and stroke. For now, it looks like adding a third drug and focusing on life style changes would be a wise choice for Margaret. Although it is not the answer that Margaret's looking for, there's a good argument for getting her blood pressure at least below 140/90. If her blood pressure remains high as she ages, she will fall into a higher risk category, and should aim for a target of 130/80.
Keeping blood pressure lower for longer can prevent strokes and heart attacks -- and could perhaps even prevent serious complications for Margaret herself. Although it may be appropriate for some people to use 140/90 as a target blood pressure, those at higher risk for future strokes and heart attacks need to go lower.
The path forward is clear: We need to adopt lower, more difficult to achieve blood pressure targets, requiring more medications and a concerted focus on lifestyle changes.
This is the final piece in a five-part series, "Too High," created for those with high blood pressure and their family and friends. Previous blog posts addressed the prevalence of high blood pressure, the most common medications, drug side effects and the importance of lifestyle changes. Some data in this series come from QuintilesIMS. For additional information, please contact rstaff@stanford.edu.
Randall Stafford, MD, PhD, a professor of medicine and a primary care physician at Stanford. He was one of several Stanford investigators for SPRINT and is a member of a group working on soon to be released high blood pressure guidelines for the American Heart Association. He is developing practical strategies to improve how physicians and consumers approach chronic disease treatment and prevention.
Previously: Too high: Despite drugs, blood pressure rates continue to soar in the United States, Too high: Older drugs work well for hypertension, new medications show little innovation, Too high: Side effects hamper many blood pressure medications and Too high: For high blood pressure, lifestyle changes are the most effective and safest drug
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