Lower blood pressure target will save lives, study finds
When the federal government announced in September that it had abruptly halted a large blood pressure study because its results were so compelling, doctors were left in frustrating limbo.
The announcement said researchers had found that driving systolic blood pressure to levels far below what current guidelines recommend — less than 120 instead of 140 or 150 — can save lives and prevent heart disease and strokes. But they declined to release any data on the number of lives saved, the number of heart attacks prevented or other critical measures.
“How can anyone do anything different tomorrow with regard to blood pressure control without knowing more about what they found?” said Dr. Harlan Krumholz, a cardiologist at Yale, echoing the concerns of other specialists.
On Monday, reporting at an American Heart Association meeting in Orlando, Fla., and in a paper published simultaneously in the New England Journal of Medicine, study investigators lifted the veil. Among the 9,361 patients followed for an average of 3.2 years, there were 27 percent fewer deaths (155 compared with 210) and 38 percent fewer cases of heart failure (62 compared with 100) among patients who achieved the systolic pressure target of 120 than among those who achieved the current 140 target.
Systolic pressure is the higher of the two blood pressure numbers and represents pressure on blood vessels when the heart contracts.
Overall, there was a 25 percent reduction — 243 compared with 319 — in people who had a heart attack, heart failure or stroke or died from heart disease, Dr. Paul K. Whelton, a principal investigator for the study, said.
The older participants did just as well as younger ones.
For millions of Americans with high blood pressure, the results could be transformative, said Dr. Marc Alan Pfeffer, a professor of medicine at Harvard who was not affiliated with the study.
Before now, Pfeffer said, if a patient older than 50 came into his office with systolic pressure of 136 and a well-controlled risk factor for heart disease like high cholesterol, he would pat the patient on the back and say, “Great job.” Now, he said, he would feel obligated to give the patient more hypertension drugs. Otherwise, he said, “I would have lost the opportunity to help another human being.”
The study, called Sprint, enrolled patients ages 50 and older with high blood pressure. The patients also had at least one other risk factor for heart disease like smoking or a high cholesterol level, or they had kidney disease, or they were simply 75 or older. Half were assigned to a systolic pressure target below 140, in keeping with today’s medical practice. The rest were assigned a target pressure of less than 120. The study was supposed to continue until 2017, but ended abruptly in the summer when researchers announced they had “potentially lifesaving” results.
Doctors have long wrestled with how low blood pressure should go. Bringing it too far down, particularly in elderly people, can result in complications like dizziness and fainting. According to the results released Monday, about 5 percent of the study’s patients, or 220 people, with the 120 blood pressure target had serious complications over the course of the study — blood pressure so low it caused severe dizziness or fainting, or a reversible injury to the kidneys. Among those with the 140 target, 118 had serious complications.