In a prospective study of 1,935 men and women who had been hospitalized for a heart attack, the researchers found that the long-term mortality rate for women with diabetes was almost three times greater than the rate for women without diabetes. The long-term mortality rate for all people with diabetes was nearly twice that for non-diabetic people.
"Our findings confirm that diabetes markedly raises the long-term death rate of people with heart attacks, especially women," says Kenneth J. Mukamal, M.D., M.P.H., an associate physician at Beth Israel Deaconess and lead author of the study. "In light of this, diabetic patients need aggressive treatment of cardiac risk factors to prevent heart attacks, and people without diabetes should emphasize healthy lifestyle choices that may prevent diabetes, including proper diet and exercise."
Recent studies have shown that having diabetes increases a person’s risk of long-term mortality after suffering a heart attack, but the findings had limitations. Many of the studies’ post-heart attack follow-up periods lasted 12 or fewer months and most could not control for lifestyle characteristics that differ between diabetic and non-diabetic patients and may impact mortality.
In this latest study, Mukamal and his colleagues analyzed data collected through medical records reviews and face-to-face interviews with participants enrolled in the Determinants of Myocardial Infarction Onset Study. The researchers followed the participants for an average of 3.7 years after they were hospitalized for a heart attack. They also measured for a variety of lifestyle and sociodemographic factors that could distort the mortality rate, such as usual frequency of physical exertion, alcohol consumption and education attainment.
Approximately 21 percent (399) of the participants had clinically diagnosed diabetes. Twenty nine percent (116) of the diabetic participants died during the follow-up period. In comparison, 13 percent (204) of the non-diabetic participants died.
The researchers found that the long-term mortality rate for diabetic participants who survived an initial heart attack was equivalent to the rate for people who had survived a second heart attack. Previous studies have shown that diabetes and a heart attack adversely impact the heart, especially the left ventricle, in a similar manner. This could be one explanation for the comparable long-term mortality rates.
However, the researchers did not find any relationship between the length of time a participant had been diagnosed with diabetes and the risk of long-term mortality after suffering a heart attack. In addition, the type of treatment participants used to control their diabetes – insulin, oral medication or diet – did not have an impact on the mortality rate.
Mukamal says that based on their findings, he and his colleagues believe that care strategies that focus on the short-term prognosis of diabetic patients who have had a heart attack are insufficient. "It is clear that there is an immediate need for more research on specialized primary and secondary prevention strategies for diabetic patients," says Mukamal, who is also an instructor in medicine at Harvard Medical School. "Developing specialized strategies for caring for diabetic patients, such as screenings for coronary heart disease or the preferential use of bypass surgery for revascularization, may greatly improve their health and their overall quality of life."
The study’s other authors are Richard W. Nesto, M.D., Lahey Clinic Medical Center, Mylan C. Cohen M.D., M.P.H., Maine Medical Center, James E. Muller, M.D., Massachusetts General Hospital, Malcolm McClure, Sc.D., Harvard School of Public Health, and Murray A. Mittleman, M.D., Dr.P.H., Beth Israel Deaconess. The study was funded by the National Heart, Lung and Blood Institute, the National Institute on Alcohol Abuse and Alcoholism and the American Heart Association.
Beth Israel Deaconess Medical Center is a major patient care, research and teaching affiliate of Harvard Medical School and a founding member of CareGroup Healthcare System. Beth Israel Deaconess is the fourth largest recipient of National Institutes of Health research funding among independent U.S. teaching hospitals.
Journal
Diabetes Care