Blood Pressure Treatment Targets: Did They Change Again?

Landmark study (SPRINT Trial) explained in simple English

SPRINT Trial has changed blood pressure targets for some people. Getty Images/Chris Ryan

DID WE MOVE THE GOALPOST YET AGAIN ON BLOOD PRESSURE TREATMENT TARGETS

A year or so ago, I wrote an article about the changing guidelines for treatment of blood pressure.  I went over the fact that the way be treated blood pressure, and even when we treated, is not entirely dependent on a physician's opinion, and that there are "guidelines" to help the doc sitting out there in the "trenches" treating this ubiquitous problem.

Now, it would be ok if there was one uniform set of guidelines; but last I checked, the number of well-meaning organizations doling out blood pressure treatment advice was close to approaching the double digits.

While one set of physicians believe that this is unnecessary bureaucracy which hampers customization of blood pressure treatment, the counter side believes that guidelines distill the most current evidence and improve  patient outcomes. Both sides have a point. Evidence-based medicine is never meant to be "cookbook medicine", as they say.  Therefore, any data or conclusion, no matter how strong it is, cannot be applied blindly to the individual patient. What applies to a large population might not work at an individual level. For the patient hoping to get his blood pressure controlled with minimal adverse effects, the only that matters is their well-being, and that is how it should be.

Therefore, at the end of the day, nothing is more important than that discussion between the patient and physician keeping the goals and expectations of hypertension treatment, risks of under or over-treatment, and medication side effects in mind.

SO WHY IS TREATING BLOOD PRESSURE SO COMPLICATED FOR PHYSICIANS?

I will not go over the importance of treating elevated blood pressure.

I have covered that in other articles. High blood pressure is the second most common cause of kidney failure after diabetes in most regions. It is also a leading cause of heart attacks, heart failure, stroke etc.

Given the above, one finds it hard to imagine what is the brouhaha about. Seems obvious and intuitive, right? High blood pressure is bad, so treating it and lowering it must be good?  Well, in science and medicine, things are never that straightforward. There are still basic questions in the field that we still haven't fully answered. Here are a few examples:

  • Is high blood pressure a disease, or is at a risk factor? (Not the same thing)
  • Could hypertension just be an innocent bystander; something that happens when our blood vessels stiffen as we age?  And if that is the case, should our energies be directed at reducing the arterial stiffness, rather than lowering the pressure?
  • We know high blood pressure is associated with increased risk of death. That is a fact that we observed very early on from epidemiological studies. But can you use those data to conclusively suggest that lowering it will lower your risk of death? In other words, are you improving the outcome, or are you just lessening the risk? Again, these two corollaries are not necessarily synonymous.

    ​Let me stop there before I confuse you more.  Let's talk about how we currently treat this thing.

    ​HOW DO WE CURRENTLY TREAT HIGH BLOOD PRESSURE

    A year ago, I detailed the most commonly followed guidelines for treatment of blood pressure in the United States. These are the much-vaunted Joint National Committee (JNC) guidelines.  The latest version, JNC-8, had set forth certain thresholds for initiating treatment, as well as goals to which the patient should be treated. Let me recap real quick:

    • Patients younger than 60 yrs: the target is to keep them under 140/90 mmHg
    • Patients older than 60 yrs: the target is to keep them under 150/90 mmHg

    Targets could be different for some subsets of patients (like those with kidney disease, heart failure, history of stroke, protein in the urine, etc) depending on who you ask! Besides the target (the destination), how you get there (the journey- or in your case, the medications you use) is also important. Therefore, there could be coexistent disease conditions which create "compelling indications" for physicians to favor a certain type of blood pressure medication over the others.

    ARE THE RECENT JNC-8 BLOOD PRESSURE TREATMENT RECOMMENDATIONS ALREADY OUT OF DATE? 

    We still don't know for sure.  But in late 2015, a big hypertension treatment study, called the SPRINT (Systolic Blood Pressure Intervention) Trial garnered a lot of attention.  The results of the trial might potentially change treatment targets for a significant number of patients.  Here is a summary of what the trial was.

    THE SPRINT TRIAL: BACKGROUND

    The results of the SPRINT Trial were published in the New England Journal of Medicine in November 2015. The trial was funded by the National Institutes of Health (NIH), and one of the cosponsor was the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). This itself gives the trial's results a degree of legitimacy that is often not bestowed on drug company sponsored trials. This was a large study that ran across 102 centers and included over 90,000 participants.

    I will not go into the details of what were the criteria for inclusion, (you can take a look at a video here for a quick overview), but I do want to emphasize that diabetics were not included in the study.  A good fraction of patients, almost a third in fact, had chronic kidney disease. This makes it one of the largest hypertension trials in kidney disease patients.

    WHAT WAS THE NEED FOR THE SPRINT STUDY

    The fundamental question that the study tried to answer was whether treating nondiabetic patients to a target blood pressure of less than 120 (intensive treatment group) might actually be more beneficial than treating them to less than 140 (standard treatment group)- as, for instance suggested by the current JNC 8 guidelines. This dichotomy with JNC 8 might in part be related to the fact that JNC 8 guidelines drew some conclusions from another major study that was done on diabetics with high blood pressure (the ACCORD Trial- which showed that intensively lowering blood pressure to a target of less than 120 did not reduce risk of death in diabetic patients). 

    WHAT DO RESULTS OF THE SPRINT TRIAL TELL US

    The difference in outcomes between the two groups was stark. Let me summarize:

    • In the group of patients that was treated intensively toward target blood pressure of less than 120 mmHg,  there was almost a 25% lower relative risk of a combined endpoint of myocardial infarction, acute coronary syndrome, stroke, acute heart failure, and cardiovascular death
    • Intensively treated patients saw a 27% lower risk of death from any cause

    Given such a big difference between the two groups, the trial was actually stopped earlier than expected in August 2015 because of such significant reduction in risk factors and endpoints (originally the trial was supposed to run for 5 years until the end of 2016).

    WHAT DOES THIS MEAN FOR THE PATIENT? DO YOU NEED TO GO BACK TO YOUR PHYSICIAN AND TREAT YOUR HIGH BLOOD PRESSURE MORE AGGRESSIVELY NOW? 

    It depends. As I mentioned above, evidence-based medicine is not cookbook science.  Just because a major well-designed trial showed positive results, it does not necessarily mean that the results are applicable to you at an individual level.

    Here are a few points you might want to discuss with your physician regarding the implications of these new findings:

    1. The trial did not include diabetics. A significant number of patients with high blood pressure also happen to be diabetics. Hence, the results might not apply to you if you happen to have diabetes as well (for that, take a look at the ACCORD trial that I mentioned earlier which had not shown any benefit of intensive control; in which case your target may still be treatment to a level of less than 140, and not 120).
    2. SPRINT trial included older patients who were high risk for cardiovascular disease (heart attacks, strokes, kidney disease etc). If you think you fit this profile, or are not sure, talk to your physician about the results. There is evidence that patients with mild hypertension who are otherwise low risk for cardiovascular disease might not benefit from treatment of mildly elevated blood pressure.  Take a look at this major meta-analysis here.  
    3. The trial did note some side effects of intensive treatment.  There was a slightly higher relative risk of kidney injury, and more frequent ER visits for loss of consciousness, low blood pressure, and electrolyte abnormalities.  Although, the absolute increase in risk of these problems might not have been that high, these data may be significant enough for some patients to not consider aggressive treatment perhaps.
    4. Not everyone can tolerate lower blood pressures.  As we age, our blood vessels become more stiff. Therefore, while patients with "soft" blood vessels (good arterial "compliance") might do okay with these aggressive targets, patients with stiff arteries might not. One way to find out if you have stiff arteries is to look at your diastolic blood pressure. Low diastolic blood pressures in older age group could be indicative of stiff arteries. 
    5. Finally, the results might not apply well to patients with a history of falls, vertigo, or patients who are frail.  They have been studies done before that have shown that frail adults may not benefit from blood pressure treatment at all! In this study in fact, a higher blood pressure was associated with a low risk of death in frail elderly adults. 

    ​THE TAKE HOME MESSAGE

    The results from the SPRINT Trial might be applicable to a large fraction of US population who fit the criteria of the trial. However, the results are nowhere close to being considered universal guidelines for everyone. Certain older non-diabetic patients with high cardiovascular risk may benefit from intensive reduction in the blood pressure is to less than 120 mmHg.

    If you still not sure, talk to your Hypertension Specialist!  

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