Are you caring for an older person with hypertension, also known as high blood pressure? Or does your parent take medication to lower blood pressure?
If so, you are probably wondering just what is the right blood pressure (BP) for your older relative, especially given the recent publication of the Systolic Blood Pressure Intervention Trial (abbreviated as “SPRINT”) research results.
This study first made headlines in September 2015, in part because the findings seemed to contradict the expert hypertension guidelines released in December 2013, which for the first time had proposed a higher goal BP ( a systolic BP of less than 150mm mercury) for most adults aged 60 or older.
In particular, SPRINT randomly assigned participants — all of whom were aged 50 or older, and were at high risk for cardiovascular events — to have their systolic blood pressure (that’s the top number) treated to a goal of either 140, or 120. Because the study found that people randomized to a goal of 120 were experiencing better health outcomes, the study was ended early.
For those of us who specialize in optimizing the health of older adults, this is obviously an important research development that could change our medical recommendations for certain seniors.
But what about for you, or for your older relative? Do the SPRINT results mean you should talk to the doctor about changing your BP medications?
Maybe yes, but quite possibly no. In this article, I’ll help you better understand the SPRINT study and results, as well as the side-effects and special considerations for seniors at risk for falls. This way, you’ll better understand how SPRINT’s findings might inform the BP goals that you and your doctors choose to pursue.
Here’s what this post will cover regarding the SPRINT study:
- Who was included and excluded from SPRINT, and what the research intervention involved, including the type of BP medications that were used most often
- What the actual likelihood of benefits and harms was within SPRINT, and what you might expect if you are similar to the SPRINT participants
- Why you probably need to make a change in how your blood pressure is measured before considering a SPRINT-style systolic BP goal of 120.
- What this means for new blood pressure guidelines
[Note: This original version of this post explained why I supported the December 2013 blood pressure guidelines suggesting a higher BP treatment goal for most older adults. You can still find that content in the bottom part of the post, along with a link to a handy cheatsheet I developed to help family caregivers check an older person for worrisome BP, or risky drops in BP when standing.]
Who was — and wasn’t — studied in the SPRINT blood pressure trial
Do the study results apply to you or your older relative? This is one of the two most important questions to ask yourself, when you hear exciting news about clinical research. (The other question to ask is “What’s the “number needed-to-treat,” which corresponds to your odds of actually benefiting; more on that below.)
Why? Because a well-done medical study tells us what health outcomes happened when we applied a certain intervention to a certain group of people. If you aren’t like the people who were studied, then there’s a higher chance you won’t experience the benefits that study participants did.
So who was in SPRINT? Here are the criteria the researchers used to define the study group, and enroll participants.
What the SPRINT participants were like:
- Aged 50 or older, systolic blood pressure of 130-180mm mercury, and at “increased risk of cardiovascular events.”
- At increased risk for cardiovascular disease, which was defined by meeting one of the following conditions:
- Aged 75 or older. Yep, that in of itself puts people at risk.
- A 10-year risk of cardiovascular disease of 15% or greater on the basis of the Framingham risk score. You can check your own Framingham risk score here; you’ll need to know your total cholesterol, HDL cholesterol, and systolic blood pressure.
- Chronic kidney disease, defined by an estimated glomerular filtration rate (eGFR) of 20-60.
- Clinical or subclinical cardiovascular disease other than stroke. This means things like a history of heart attack, bypass surgery, peripheral artery disease, carotid artery stenting or surgery, or any testing considered “positive” for cardiovascular disease. For a full list of criteria, see the published study’s supplemental materials here.
It’s equally important to consider who was excluded from SPRINT. You may have already heard that SPRINT didn’t cover people with diabetes or stroke, but the exclusion list is much longer than that. (See the study appendix for the full detailed list.)
What the SPRINT participants were not like: Older persons with any of the following diagnoses, conditions, or circumstances were not eligible for the study:
- Past stroke
- Clinical diagnosis of dementia, and/or being on dementia medication
- People residing in a nursing home. (Assisted-living was ok.)
- Substance abuse (active or within the past 12 months)
- Symptomatic heart failure within the past 6 months or left ventricular ejection fraction (by any method) < 35%
- Polycystic kidney disease or eGFR < 20
- “Significant history of poor compliance with medications or attendance at clinic visits.”
As you can see, quite a lot of common diagnoses and circumstances were grounds for exclusion from the SPRINT study.
Ultimately, 9361 people were enrolled between November 2010 and March 2013. The average age was 68, and 28% of participants were aged 75 or older.
Surprisingly to me, the average systolic blood pressure at baseline was 140, which struck me as better BP control than average older adults. And only 34% of participants had a systolic blood pressure higher than 145 at the start of the study. (For comparison, the CDC reports that only 52% of people with hypertension have it adequately controlled.)
On average, at the start of the study participants were taking two blood pressure medications.
What did the SPRINT intervention involve?
SPRINT participants were randomly assigned to be treated to a systolic BP goal of either 140, or 120.
Participants were seen once a month for the first three months, and then every 3 months after that.
To treat blood pressure, SPRINT provided all the major classes of BP medication for free, and also allowed clinicians to use other BP medications if they saw fit. Here are the main classes of medication used; I’ve organized them roughly by how commonly they were used (per table S2 of the appendix).
Blood Pressure Medications Used in SPRINT:
- Angiotensin converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs), e.g. lisinopril, losartan
- Diuretics, e.g. chlorthalidone, hydrochlorothiazide, furosemide, spironolactone
- Calcium-channel blockers, e.g. diltiazem, amlodipine
- Beta-blockers (encouraged for those with coronary artery disease), e.g. metoprolol, atenolol
- Alpha-one blockers, e.g. doxazosin
- Direct vasodilators, e.g. hydralazine, minoxidil
- Alpha-two agonists, e.g. clonidine
Those last three classes of BP medication were used in 10% of people or less, which makes sense as none of them are recommended as first-line medication choices for hypertension, heart conditions, or kidney disease.
What about non-drug methods to manage high blood pressure?
In the scholarly publication, the SPRINT investigators say that “Lifestyle modification was encouraged as part of the management strategy,” but they don’t provide more specifics on what modifications were encouraged or how. So it’s hard to know how any non-drug methods — diet, exercise, salt reduction, stress reduction — might have factored into this study.
Benefits and Harms Observed in SPRINT
SPRINT randomly divided participants into an intensive-treatment group, which aimed for systolic BP less than 120, and a standard-treatment group, which aimed for systolic BP less than 140.
After one year, the average systolic BP among the intensive-treatment group was 121, compared to 136 among the standard-treatment group. The intensive group required an average of 2.8 medications to reach their lower BP goal; the standard group required an average of 1.8 medications.
The follow-up period averaged about three years.
Benefits of intensive BP treatment:
During follow-up, 1.65% per year of people in the intensive-treatment group and 2.19% per year of people in the standard-treatment experienced a significant cardiovascular “outcome event”: a heart attack, a stroke, acute decompensated heart failure, or death from cardiovascular causes.
The study authors calculated that “The numbers needed to treat to prevent a primary outcome event, death from any cause, and death from cardiovascular causes during the median 3.26 years of the trial were 61, 90, and 172, respectively.”
In other words, if you are like the study participants, and if you decide to switch from a systolic BP goal of 140 to a goal of 120, over a few years you’ll have:
- A 1 in 61 (1.6%) chance of avoiding a cardiovascular event
- A 1 in 90 chance (1.1%) chance of avoiding death from any cause
- A 1 in 172 chance (0.6%) chance of avoiding death from cardiovascular causes
Harms of Intensive BP Treatment
The SPRINT investigators were careful to track side-effects and complications. They found that serious adverse events occurred in 38.3% of the intensive-treatment group and in 37.1% of the standard-treatment group.
Adverse events included problems like hypotension (low blood pressure), syncope (passing out), electrolyte problems, declines in kidney function, and injurious falls. Most problems affected 1-7% of participants, with the exception of orthostatic hypotension — which means BP dropping with standing — which affected 16-18% of participants. (Standing BP was checked at baseline, 1, 6, and 12 months and yearly thereafter.)
Although many side-effects were a little more common in the intensively-treated group, injurious falls were equally common in both treatment groups, and affected 7.1% of participants.
This finding is actually consistent with what was reported in a 2014 study of serious falls (e.g. bone-breaking falls) in older people with high blood pressure. In that study, the researchers classified people as being on no BP medication, moderate-intensity BP treatment, or high-intensity BP treatment. Moderate- and high-intensity treatment was linked to a nearly equivalent risk of falling over three years (about 8.5%), whereas 7.1% of seniors on no BP medication had a bad fall.
How Blood Pressure Was Measured in SPRINT
Blood pressure was measured a very careful way that is quite different from the way patients usually have BP measured by their doctors. Here’s what they did in SPRINT:
- Had people sit down and rest for five minutes before checking BP
- Checked BP three times consecutively, using an automated BP monitor (Omron 907)
- Used the average of those three BP measurements to assess the person’s BP and determine whether medications should be adjusted up or down.
Obviously, this is not the experience that most people have in the doctor’s office, and likely led to lower BP measurements than those taken under usual circumstances.
If you are similar to a SPRINT participant and are thinking of aiming for a lower BP goal, be sure to request that your BP is checked in a similar way. In truth, it’s a much sounder basis for changing a patient’s medications, but it’s not usual care at this time.
Does SPRINT mean New Blood Pressure Guidelines?
Briefly, no. Or in any case, not yet. That’s in part because guidelines are the result of some expert group going through a very careful process of evidence review and synthesis. So it will take a while before any reputable group can synthesize SPRINT into the existing medical evidence, and finalize guidelines to be released to clinicians and the public.
Now, that doesn’t mean that some doctors won’t be attempting to get patients to a lower blood pressure goal right away. But it’s not clear that this should be done for most patients, and at a minimum, people should know that if they are like the SPRINT participants — which they probably aren’t — aiming for the lower BP goal likely gives them a 0.5%-1.5% chance of avoiding a bad health outcome. (Whereas they will have a very high percent chance of having to take more medication every day.)
In fact, I thought it was quite funny that the NYT headline reporting on SPRINT proclaimed “Data on Benefits of Lower Blood Pressure Brings Clarity for Doctors and Patients,” because many doctors have gone on the record with a more nuanced assessment. The NYT itself published a sensible commentary by a well-regarded cardiologist, Dr. Harlan Krumholz, which I would highly recommend: “3 Things to Know About the Sprint Blood Pressure Trial.”
As Dr. Krumholz points out, most people who currently have high blood pressure would not have qualified for SPRINT. It’s especially notable that people with diabetes were excluded; that was in part because a similar well-done study called ACCORD found that intensively treating the blood pressure of people with diabetes did not reduce mortality.
(An added little twist to consider: Yet another research group has studied clinical trials that end early, and found that studies that end early usually report bigger effects than studies that don’t end early. See this JAMA article.)
Personally, I agree with Dr. Krumholz’s conclusions:
- These results should not be considered a mandate for people to run out and get treated so their blood pressures are below 120.
- The potential benefits of lowering blood pressure must be weighed against the harms.
- We need more information about the balance of risks and benefits for each person so that the choice can be personalized.
In terms of my personal practice: I see a lot of older people who are worried about falls, and a well-done study published in 2014 found that blood pressure treatment was associated with serious — as in, bone breaking — falls. (Read my coverage of this study here.)
I also find that many of my patients are struggling to manage multiple medications, and are at risk for interactions from their medications. For instance, all the medications used in SPRINT have side-effects to watch out for, and many can interact with other medications or chronic diseases.
There is indeed good scientific evidence that for those older adults who have a systolic BP in the 160s or higher, getting them down to a systolic in the 140s does reduce the chance of strokes and other serious cardiovascular diseases. (See here and here.) So it’s certainly important to identify serious hypertension in seniors, and treat it if possible.
But given the relatively small absolute benefit of aiming for a systolic blood pressure of 120, I expect that for most of my patients, aiming for a systolic BP in the 140s will remain reasonable.
Now, you are likely still wondering what’s the right blood pressure goal for your older relative. I can’t tell you for sure for your particular situation. But here’s more information on why to be careful about over-treating high blood pressure, and why I agreed with the December 2013 guidelines recommending a systolic BP goal of 150 for most seniors.
Why Seniors Should Watch Out for Over-Treatment of High Blood Pressure
In my experience, many older adults are taking more BP medication than they need, meaning they’ve reached a point at which the risks and burdens outweigh the benefits (compared with less aggressive treatment of high blood pressure).
This can cause falls or dizziness due to orthostatic hypotension, and one of the most common medication changes I implement as a geriatrician is the cutting back of blood pressure medications. (For more on orthostatic hypotension, see this article at HealthinAging.org, and also this FAQ I wrote about why elderly people get dizzy when standing up.)
If you want to read a longer article that I wrote on this topic, shortly after the December 2013 high blood pressure guidelines were released, see my post at AgingCare.com:
AgingCare.com only publishes articles that won’t be published elsewhere on the web, so I can’t post the whole thing here. But here are the highlights related to the December 2013 BP guidelines:
- A higher target BP for adults aged 60 or older. The recommended goal BP is now less than 150/90, instead of less than 140/90 (which was the target recommended in prior guidelines, published in 2003).
- A higher target BP for people with diabetes and/or kidney disease. The recommended goal BP is now less than 140/90, instead of less than 130/80.
What does this mean for you, if you’re caring for aging parents or other older persons? It means you should check on how their BP has been doing.
If it’s been much lower than the numbers above, you should consider discussing the BP medications with your parent’s doctor. This is especially important if you’ve had any concerns about falls or balance. For specific recommendations on how to make sure your older loved one isn’t getting too much blood pressure medication, read my full article at AgingCare.com. I also offer tips on checking BP in this post: Why I Love Home Blood Pressure Monitors.
Related Post: A recently published study found that older adults on BP medications have more serious falls. You can read my blog post about it here.