Declaring they had "potentially lifesaving information," federal health officials said on Friday that they were ending a major study more than a year early because it has already conclusively answered a question cardiologists have puzzled over for decades: How low should blood pressure go?
The answer: way lower than the current guidelines.
For years doctors have been uncertain what the optimal goal should be for patients with high blood pressure. The aim of course is to bring it down, but how far and how aggressively remained a mystery. There are trade-offs — risks and side effects from drugs — and there were lingering questions about whether older patients needed somewhat higher blood pressure to push blood to the brain.
The study found that patients who were assigned to reach a systolic blood pressure goal below 120 — far lower than current guidelines of 140, or 150 for people over 60 — had their risk of heart attacks, heart failure and strokes reduced by a third and their risk of death reduced by nearly a quarter.
The study, called Sprint, randomly assigned more than 9,300 men and women ages 50 and over who were at high risk of heart disease or had kidney disease to of two systolic blood pressure targets: less than 120 millimeters of mercury, which is lower than any guideline ever suggested, or less than 140. (Systolic pressure is the higher of the two blood pressure numbers and represents pressure on blood vessels when the heart contracts.)
The study was expected to conclude in 2017, but considering the results of great importance to public health, the National Heart, Lung and Blood Institute announced them Friday morning, saying a paper with the data would be published within a few months.
"This study provides potentially lifesaving information," Dr. Gary H. Gibbons, director of the institute, said in a statement announcing the decision.
Nearly 79 million adults in this country — one of three — have high blood pressure, and half of those being treated for it still have systolic pressures over 140.