For much of the previous century, little research examined the differences between men and women in health and illness. But things changed after a landmark report was published by the Institute of Medicine in 2001, Exploring the Biological Contributions to Human Health: Does Sex Matter? With cardiovascular disease now the leading cause of death among women in the United States, research on heart disease in women is in the spotlight. The American Heart Association, as part of its February focus on women's heart disease, hosted a women's "State of the Heart" Webcast, presenting what it considered important new research from the past year. Here are some of the highlights.
Not sick enough. According to Caroline Daly, lead author of a European study on the differences in the treatment of angina in men and women, women were less likely than men to be evaluated with exercise electrocardiography. But even with a positive exercise test result, women were less likely than men to undergo angiography (56% versus 65%, respectively). Women were also less likely than men to receive antiplatelet therapy (93% versus 95%) or lipid-lowering therapy (76% versus 79%), as well as revascularization procedures (13% versus 29%). After one year of follow-up, women with coronary artery disease were twice as likely as men to have died from a myocardial infarction-perhaps, Daly says, because they receive less aggressive treatment. "Women must prove they are very ill to get aggressive treatment," she says.
Missing CABG patch? A Canadian study that followed, for eleven years, more than 66,000 patients (22% were women) who'd undergone coronary artery bypass grafting found that although long-term survival rates were similar, women were one and a half times more likely than men to need readmission for unstable angina or heart failure. Author Veena Guru noted that the women had received fewer grafts than the men and postulated that the disparity in angina and heart failure rates might be due to the type or number of arterial grafts performed.
Fit and trim. As part of the Nurses' Health Study, in which researchers followed more than 88,000 female nurses for 20 years, Frank Hu and colleagues evaluated which was more predictive of the development of coronary heart disease, physical inactivity (measured by a questionnaire) or overweight or obesity (obesity was defined as a body mass index of 30 or higher; a score between 25 and 29.9 indicated overweight). The findings were sobering but not surprising: to lower risk, women should be both fit and trim.
Obese women who were also sedentary (exercising less than an hour a week) were three and a half times more likely to develop coronary heart disease. Those who were obese but active were two and a half times as likely to develop it. And lean but sedentary women carried one and a half times the risk. He emphasized that although obesity and physical inactivity are each strong and independent predictors of coronary heart disease, "physical activity attenuates but does not eliminate risk."
And of course, smoking compounded the risk of heart disease in women who were both obese and inactive; their risk was nearly nine times that of active, normal-weight women.
Riding the wave. Using data from more than 38,000 women participating in the Women's Health Initiative, researchers evaluated electrocardiograms to determine whether abnormalities might predict adverse cardiac events. Study author Pentti Rautaharju explained that T wave abnormalities, which mark the repolarization or recovery of the ventricles and have historically been ignored, deemed "nonsignificant, in women," were actually associated with a higher risk of coronary heart disease and new heart failure. A widened QRS-T angle conferred a three-fold increase in the risk of death; a two-fold increase in the risk of congestive heart failure was associated with electrocardiographic findings of an old, silent myocardial infarction or decreased heart rate variability. Rautaharju emphasized that "T wave abnormalities in post-menopausal women warrant serious attention."
Cardiac rehabilitation. In response to a question about the effects of cardiac rehabilitation on discharge outcomes, Lori Mosca, lead author of a national study evaluating women's awareness of heart disease and its prevention, said, "We know cardiac rehabilitation increases survival, but in the United States, women are less likely than men to be referred. They are also more likely to drop out."