From Yale University
Blood transfusions drastically reduce death in anemic elderly heart attack patients Yale researchers have found that giving blood transfusions to anemic elderly heart attack patients significantly improves the survival rate for that group.
"This is the first study to highlight the important link between anemia, blood transfusion and mortality among elderly patients hospitalized for a heart attack," said principal investigator Harlan M. Krumholz, M.D., associate professor of medicine in the Departments of Medicine and Epidemiology and Public Health at Yale School of Medicine. "Our principal finding is that a low hematocrit, or blood count, on admission is associated with higher mortality rates in elderly heart attack patients. However, blood transfusions, when given to these patients, can significantly decrease their mortality risk."
Published in the October 25 issue of the New England Journal of Medicine, the study looked at 78,974 elderly patients in the United States age 65 or older who were hospitalized with acute myocardial infarction (heart attack) between January 1994 and February 1995.
"Surprisingly, we found that 43.4 percent of elderly patients hospitalized with a heart attack are anemic, or have a blood count below 39 percent at the time of admission," said co-author Saif Rathore, a lecturer in the Department of Medicine at Yale.
The authors also found that 30-day mortality rates were more than doubled (38.7 percent vs. 17.2 percent) in the most severely anemic patients (blood count level of 5.0 percent to 24.0 percent) compared with patients who were not anemic (blood count level 39.1 percent to 48.0 percent). Despite this higher mortality risk, less than one-quarter (24.1 percent) of patients with clinically significant anemia (a blood count level of 33 percent or less) received a blood transfusion.
Blood transfusions, however, can significantly reduce an anemic patient's mortality risk. "Our data indicate that blood transfusions provided to elderly anemic patients can significantly reduce their risk of short-term mortality," said Krumholz. "Most promisingly, our data indicate this benefit is observed in elderly patients with blood count levels as high as 33 percent, a higher level than previously considered by clinicians. These data are particularly compelling given the lack of clinical guidelines directing hematocrit levels at which to provide transfusion in elderly patients with heart disease."
In an editorial accompanying the study, Lawrence Tim Goodnough, M.D., and Richard G. Bach, M.D., of the Washington University School of Medicine, underscore the importance of these findings. "For the first time, we have evidence that patients with a specific clinical presentation are affected adversely by the underuse of transfusion," Goodnough and Bach write. They further suggest on the basis of this research "that hematocrit levels should be maintained above 33 percent in patients who present with acute myocardial infarction."
The study's authors agree. "We certainly feel that our findings should result in a change in clinical practice," said first author Wen-Chih Wu, M.D., of Brown University.
Krumholz said the findings are a product of the team's long-standing association with the Centers for Medicare and Medicaid Services, the federal agency that conducted that Cooperative Cardiovascular Project.
"These data underscore the importance of investigating the unique challenges of heart disease in elderly patients, particularly given the demographic changes in our nation's population," said Krumholz. "Conditions such as anemia and appropriate treatments for these conditions, such as blood transfusion, require specific evaluation in elderly patients because of the many factors that guide treatment in this population."
Other authors on the study include Yongfei Wang and Martha J. Radford, M.D., of Yale School of Medicine.