It’s not often that a clinical trial is closed early because the findings are too good to keep under wraps.
But that’s exactly what happened September 2015 with the Systolic Blood Pressure Intervention Trial (SPRINT), a study funded by the National Institutes of Health (NIH).
The findings from this trial called into question our national standard for safe blood pressure levels for high-risk hypertension patients – individuals who are being treated with medications for high blood pressure. Until now, readings of 140/90 were considered optimal for these patients. SPRINT blew the roof off that assumption by showing that maintaining a target pressure of 120/80 greatly reduced heart attacks, stroke, and death.
High blood pressure and SPRINT
The focus of SPRINT was to determine the benefits of helping high-risk hypertension patients achieve blood pressure readings of 120/80, rather than the standard 140/90. It’s important to note that a blood pressure of 120/80 in hypertension patients and in people without hypertension has different meaning. For hypertension patients, the higher the starting blood pressure, the more they will benefit from their systolic blood pressure – the top number in the reading – being reduced by 20 or more.
Hypertension is both common and dangerous. Approximately one-third of Americans have hypertension, and the risk for developing hypertension increases with age. In fact, some physicians say it’s a disease that everyone will get if they live long enough.
Hypertension is a major risk factor for heart disease, stroke, and kidney failure. Contrary to a widely held belief, patients can’t feel elevations in their blood pressure. In other words, you simply cannot tell if your blood pressure is high, which is why hypertension has been called the “silent killer.”
SPRINT began in the fall of 2009. More than 9,300 male and female participants were recruited from medical centers throughout the United States and Puerto Rico, including 148 UT Southwestern patients. Participants were 50 years of age or older and had at least one risk factor for heart disease. The study also included kidney disease patients.
Dr. Rober Toto was the principal investigator for UT Southwestern in the trial, which is the largest study of its kind to date. During the trial, randomized participants’ blood pressure medications were carefully adjusted to achieve a target pressure of 120/80.
The results of the trial were substantial. Compared with data from patients who maintained 140/90 readings, patients who maintained the target pressure of 120/80 had:
- Almost a third fewer cardiovascular events such as heart attack, heart failure, and stroke
- Nearly a one fourth reduction in risk of death
What this means for hypertension patients
So should you reach out to your physician right away to adjust your medications? At this point, the answer is no.
First, we have not seen all the findings from the study. Patients may encounter unexpected side effects if they are treated too aggressively. Evidence over the years has suggested that we can lower blood pressure too much or too quickly using medications.
Over time, our organs develop defense mechanisms against hypertension. Rapidly decreasing blood pressure – instead of gradually decreasing it – can cause problems.
These problems can include:
- Physical instability
- Kidney and liver dysfunction
Second, this is only one study. Even though SPRINT was a large, rigorous trial, it’s possible that other trials may come to different conclusions. Blood pressure experts around the world settled on a drug-adjusted blood pressure of 140/90 as adequate and optimal for hypertension patients on medication, including older patients whose arteries become hardened and stiff. More research may be needed to determine if 120/80 is safe for all hypertension patients.
In science, we never stop questioning and learning, and we all benefit from the endless progress. Without question, SPRINT will influence how we approach blood pressure treatment for years to come. With time, we may emerge with more aggressive blood pressure treatment targets to tame the silent killer of hypertension.
Learn more in-depth information about the SPRINT trial on the NIH website.