Doctors Can Predict Heart Failure Death
Study stratifies risk depending on other factors
WEDNESDAY, Nov. 19, 2003 (HealthDayNews) -- A quick analysis of patients hospitalized for heart failure can pick out those at highest risk of dying, Canadian physicians report.
"We found that a simple model using data available in the initial hours of hospital presentation predicted mortality in hospitalized heart failure patients at 30 days and one year," says a report in the Nov. 19 Journal of the American Medical Association by a team at the University of Toronto.
The model fills a gap in medical practice, says study leader Dr. Douglas S. Lee.
"Up to this point in time, there have been essentially no methods for clinicians to measure the prognosis for heart failure patients in the real world," Lee says. "Evidence from clinical trails has been useful, but participants in those trials tend to be different from the patients we see in everyday life. They generally are younger, in better health, and with fewer co-morbid conditions."
Lee and his colleagues collected comprehensive data on more than 4,000 patients admitted to hospitals in the province of Ontario between 1997 and 2001 for heart failure, a progressive loss of the ability of the heart to pump blood.
Heart failure is known to be a warning sign of trouble ahead. Previous studies have found a one-year death rate in heart failure patients in the neighborhood of 40 percent. The Toronto researchers say they were able to assess the risk of individual patients by measuring factors such as blood pressure, respiratory rate, and blood levels of sodium and urea nitrogen, and by including other medical problems, formally known as co-morbid conditions -- lung disease, dementia such as Alzheimer's disease, cirrhosis of the liver, and so on.
Following the patients after their hospital admissions, the Toronto researchers were able to identify the factors that predicted the risk of death. "The strongest predictors were kidney function, blood pressure and age," Lee says.
There was a striking difference between patients facing the highest and lowest risk, he says. "The mortality rate in the highest-risk group at one year was 79 percent," Lee says. "In the lowest-risk group it was 7 percent, a tenfold difference."
"We hope that the data from this study can be used to identify patients who may need closer monitoring and more aggressive intervention," he says. "A patient admitted with heart failure in the high-risk category potentially could be admitted to a monitored or intensive care setting, rather than a hospital ward. And future research may show whether intervention in the high-risk group can lower their risk."
It's hoped that other doctors will pick up the study and extend its results. "We're interested in what kind of feedback we get," Lee says.
The reaction of Dr. Richard B. Devereux, professor of medicine at Weill Medical College of Columbia University, is that the study "is the right way to develop a predictive model."
"It is a very nice job of looking at a number of things that are individually well known to be associated with risk and producing a comprehensive model," Devereux says. "This is very nice medical science."
It's a model that can be put to work without much difficulty, Devereux says: "Something that can be easily put into a computer to see how well it predicts outcome in other populations."
Devereux is co-author of a paper in the November issue of the American Journal of Hypertension about a warning sign of danger in people with high blood pressure. An analysis of studies of more than 1,000 patients shows that enlargement of the left ventricle, the main pumping chamber of the heart, signals that aggressive treatment is needed to reduce the risk of heart attack, stroke and other cardiovascular problems, the report says.
"Left ventricular hypertrophy has long been known as an indicator of risk," Devereux says. "What has not been known before is that reversing it is beneficial to patients."
No special treatment is needed to reverse the enlargement and bring the heart muscle back to normal, he says, just greater attention to the standard methods of controlling blood pressure, such as medication and weight loss for obese people. "All blood pressure lowering treatments have beneficial effects," he says.