Nighttime Blood Pressure Linked to Heart Failure
Absence of normal drop more than doubles the risk, study finds
TUESDAY, June 27, 2006 (HealthDay News) -- People whose blood pressure doesn't go down a bit at night may be at high risk of developing congestive heart failure, a potentially fatal condition, a Swedish study found.
"Our data indicate that non-dipping is a strong risk factor, with high relative risk (approximately 2.3 times) after adjustment for established risk factors," said Dr. Erik Ingelsson, a research fellow at Uppsala University and lead author of the report in the June 28 Journal of the American Medical Association.
Previous studies have shown that the absence of the nighttime dip in blood pressure that occurs in most people as they sleep is associated with medical problems, Ingelsson said.
"This study adds to the current knowledge about the importance of nighttime blood pressure patterns by adding heart failure to the outcomes predicted by an increased nighttime blood pressure," he said.
Congestive heart failure, in which the heart loses its ability to pump blood, is one of the deadliest cardiac conditions, with patients facing a two-in-three chance of dying within five years, the researchers noted. High blood pressure is known to be a major risk factor for the condition.
The Swedish project included 951 older men who were free of major heart problems and whose blood pressure was monitored for 24 hours when they entered the study between 1990 and 1995. By 2002, 70 of the men had developed heart failure. An analysis that accounted for other risk factors, such as smoking, diabetes and cholesterol levels, found the greatest increased risk was among men whose blood pressure did not dip at all during the night.
But it's not at all certain that one possible preventive measure -- 24-hour blood pressure monitoring -- would be an effective step in spotting and preventing the problem, Ingelsson said.
"Since a non-dipping blood pressure pattern is not very common in the population -- approximately 6 percent in our population -- the importance on a population level obviously is lower than some of the main risk factors of heart failure," he said.
Dr. Deepak L. Bhatt, associate director of the Cleveland Clinic Cardiovascular Coordinating Center, said that, "from a research point of view [the study results] are fascinating. But it is important to see if we could identify people who had this pattern, then try to do something to fix it and see if it makes a difference."
Devices are available for 24-hour blood pressure monitoring, Bhatt said, adding, "I wore one of them myself for a couple of days." But they do involve "some degree of cost and some degree of inconvenience," he said. Studies are needed to determine whether that cost and inconvenience would be justified, he said.
Ingelsson agreed, in virtually the same language. "There already are several reasons for using 24-hour blood pressure monitoring, and this study adds to that. However, cost-effectiveness and interventional studies need to be done before starting to screen patients on a large scale."
Dr. Margaret Redfield, director of the Mayo Clinic Heart Failure Clinic in Rochester, Minn., added that the study "is important and is consistent with the growing awareness that what happens at night matters. I'm not sure whether we are moving to 24-hour monitoring for all patients. Perhaps this study will lead to recommendations about how important it is to measure blood pressure at night. It certainly indicates that it is."
Meanwhile, the American Heart Association and the American Diabetes Association are calling for greater prevention and treatment efforts for those respective diseases, focusing on such risk factors as high blood pressure and high blood cholesterol.
"It is long past time to start getting these risk factors under control through lifestyle changes and medication," Dr. Robert H. Eckel, president of the heart association, said in a statement.
The importance of nighttime blood pressure is described by the American Heart Association.