NEW YORK • Declaring they had "potentially life-saving 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 older who were at high risk of heart disease or had kidney disease to one of two systolic blood pressure targets: less than 120mm 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 on Friday morning, saying a paper with the data would be published within a few months.
"This study provides potentially life-saving information," Dr Gary H. Gibbons, director of the institute, said in a statement announcing the decision.
"This study will shake things up," predicted Dr J. Michael Gaziano, a professor of medicine at Harvard who was not involved with the study. He anticipated that it would have the same effect on people's thinking about blood pressure as studies about lowering cholesterol levels did when they showed that, contrary to what many had thought, the lower the number the better.
"It is outstanding news," said Dr Mark Creager, president of the American Heart Association and director of the Heart and Vascular Centre at Dartmouth-Hitchcock Medical Centre. "It will serve as a road map and will save a significant amount of lives."
NEW YORK TIMES