"Will lower blood pressure reduce the risk of heart and kidney diseases, stroke, and age-related declines in memory and thinking?"
That’s the question a team of researchers from the Intermountain Heart Institute, including myself, were trying to answer as part of an exciting groundbreaking clinical trial that was conducted in collaboration with the National Institutes of Health.
The SPRINT Trial aimed to determine the optimal systolic blood pressure in older adults, particularly those with cardiovascular disease or chronic kidney disease, and those aged 75 and older.
The results of the trial are poised to impact a significant number of people, since 75 million Americans — one out of every three adults — have high blood pressure, which puts them at risk for heart disease and stroke.
High blood pressure, also known as hypertension, is a primary or contributing cause of more than 1,100 deaths per day across the country and costs an estimated $49 billion each year in the U.S. in healthcare services, medication to treat high blood pressure, and missed days of work.
Hypertension is a silent killer; it normally sneaks up on people with no warning signs or symptoms. Many people don't even realize they have it. So when the opportunity arose to be part of the SPRINT Trial, Intermountain Healthcare immediately signed on.
NIH clinical trials are vital to studying conditions like high blood pressure, especially when there are no new drugs being tested. These kinds of studies can have tremendous impact in advancing treatments, but they’d never be conducted unless a large funding agency, like NIH, was there to sponsor them.
Blood pressure basics:
- Blood pressure is measured using two numbers. The first number, called systolic blood pressure, represents the pressure in your blood vessels when your heart beats. The second number, called diastolic blood pressure, represents the pressure in your blood vessels when your heart rests between beats. Blood pressure is measured in millimeters of mercury (mmHg).
- For adults under age 50, blood pressure less than 120/80 mmHg is considered optimal, while blood pressure of 140/90 mmHg or more is considered high. However, as people age, it’s common — and even expected — for their blood pressure numbers to rise.
- Before the study, basic medical guidelines for hypertension indicated that as long as adults over 50 kept their systolic blood pressure under 140 mmHg, they were generally considered healthy.
- The 140 mmHg guideline was put into place partially because many adults find it difficult to lower their systolic blood pressure to 120 mmHg, even with medication, which can have side-effects (like extreme lightheadedness) that can be considered as bad as having elevated blood pressure.
The SPRINT Trial challenged the hypertension guidelines and investigated whether lowering systolic blood pressure to 120 mmHg through the use of anti-hypertension medication would be more beneficial to the health of older adults than remaining at or around 140 mmHg with minimal or no medication.
Systolic blood pressure was targeted specifically because, among those 50 and older, isolated systolic hypertension is the most common form of hypertension and is significantly more important than diastolic blood pressure as a predictor for coronary events, stroke, heart failure, and end-stage renal disease.
The trial was conducted at 102 clinical sites in the United States and Puerto Rico and involved 9,361 subjects over age 50 with no history of diabetes or stroke. Subjects were divided into three categories: those with cardiovascular disease, those with chronic kidney disease, and those 75 years or older.
We started enrolling patients at the Intermountain Heart Institute in 2011 and ended up with 65 participants, all with systolic blood pressure in the 130-180 mmHg range. I had the privilege of directing our portion of the study, along with my colleagues – cardiologists, cardiology physician assistants, and internal medicine specialists as investigators.
Patients were randomized into two groups: An intensive group with a target systolic blood pressure of 120 mmHg or less, and a standard group with a target systolic blood pressure of 140 mmHg or less.
Anti-hypertension medication was dispensed on a case-by-case basis to provide the best care for individual patients, at no cost. Physicians were free to give patients any medication they felt would work best to lower systolic blood pressure within the trial parameters.
As always, safety was our number one priority. If patients in the intensive group started to feel any ill effects as their systolic blood pressure rose toward 120 mmHg, they were eased off medication. Likewise, if the blood pressure of subjects in the standard group dropped under 130 mmHg, their medication regimen was revised. Overall, we had great success in achieving the intended separation of systolic blood pressure between the two groups.
The SPRINT Trial was set to last for five years, but in August 2015, the NIH’s Data and Safety Monitoring Board stopped the trial early due to the overwhelmingly positive results within the intensive group.
By targeting systolic blood pressure to 120 mmHg, trial participants had a 38 percent lower risk of heart failure and a whopping 43 percent lower risk of death from cardiovascular causes, compared to those in the 140 mmHg target standard group. In addition, subjects in the intensive group experienced a 25 percent reduction in cardiovascular events and an impressive 27 percent reduction in death from any cause.
The results of the SPRINT Trial are absolute game changers. Simply put: findings from the study will change the way physicians treat high blood pressure.
One positive result of the study: Intermountain Healthcare’s patients are some of the first in the nation to benefit from new and improved treatment regimens for high blood pressure. Now, when I’m treating my patients, the results of the SPRINT Trial ring in my brain and I no longer accept a systolic blood pressure of 135 mmHg without at least trying to get the number down.
With the old guidelines for high blood pressure now revised to new, better standards, Intermountain Healthcare patients who are battling high blood pressure will start to see significant benefits that will improve their health and quality of life.
Because we took part in this trial, we were able to rapidly disseminate information across the Intermountain system and immediately implement new treatment standards based on the trial outcomes. This will not only improve the heart and renal health of our patients, it will also save lives!