According to the American Heart Association, cardiovascular disease claims nearly 500,000 women's lives each year, making it the number one killer among women in the United States. In fact, mortality rates due to cardiovascular disease have increased among women in past decades. Medical researchers are still searching for answers, but believe some psycho-social factors may be at work.
Susmita Mallik, MD, MPH, MS, assistant professor of medicine at the Emory University School of Medicine and internist in the Division of General Medicine at Grady Memorial Hospital, believes one of the major factors is depression. Dr. Mallik has received a four-year, $260,000 grant from the American Heart Association (AHA) to study possible links between gender, depression and outcome of acute myocardial infarction (AMI) --commonly referred to as heart attack.
"Depression is very common in patients at the time of myocardial infarction," Dr. Mallik says. "About 20 percent of patients with myocardial infarction are depressed at the time of hospitalization, and for some reason, women are twice as likely to be depressed as compared to men at the time of a heart attack. Depression, it seems, is a very important and strong risk factor of adverse outcomes post myocardial infarction."
As part of the study, 4,500 hospitalized AMI patients across the United States will be recruited. The grant will specifically compare the effects of depression on prognosis after AMI between women and men. Dr. Mallik hypothesizes that depression is a stronger predictor of adverse outcomes in women following heart attacks than men, and may explain the higher risk of adverse outcomes in women compared to men.
"At this time, we don't know clearly why women have more depression," Dr. Mallik says. "It could be that sex hormones and/or dysregulation of the stress hormone system in women who have been exposed to early trauma could play a role. Other reasons could be that women are more predisposed to psychosocial stressors, like caring for children and aging parents, lower incomes, lower education and decreased healthcare benefits compared with men. These inequities at home and work could be major stressors predisposing women to be depressed."
The study is part of a nationwide registry that includes Emory University, the University of Missouri/Kansas City, Yale, Harvard, and 15 other medical centers across the United States. The first aim of the study is to examine to what extent depression (assessed at the time of hospitalization with AMI) accounts for women's higher rates of adverse outcomes at 12 months after their heart attack. The second aim is to determine whether the association between depression -- also assessed at the time of hospitalization with AMI -- and outcomes at 12 months after AMI is the same in men and women.
The third and final aim of the study is to explore possible inter-relationships between inflammation, oxidation, depression and gender among 800 patients at Grady Hospital over the four-year study period. Dr. Mallik and other researchers will draw the blood of hospitalized Grady patients with AMI and ask them to return in two months to determine whether women have higher markers of inflammation and oxidation compared to men.
"This is the first study of its kind in the United States," Dr. Mallik says. "The AHA has really made this a priority due to the need for more awareness that women die more often after having a heart attack, and that depression is a very important risk factor for a worsened health status and higher death rates post-AMI. Since depression is such a major risk factor for worse outcomes post-AMI, AHA recommends that physicians evaluate the post-AMI patient for symptoms of depression."