(Circulation. 1999;100:e114.)
© 1999 American Heart Association, Inc.
Circulation Electronic Pages |
Women’s Heart Problems Are Poorly Understood
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Why and when women develop heart disease is both poorly understood and studied, said experts at the 21st Congress of the European Society of Cardiology, held in Barcelona. "Men and women are similar with regard to risk factors," said John Martin, MD, of the University of London Cardiology Group.
These similar heart disease risk factors include high blood pressure, high cholesterol, smoking, and age, said Dr Martin. Yet, he said, women with diabetes often have a higher risk of heart disease than men with diabetes. Women are also more likely to die of a first heart attack than men.
As with men, death rates from heart disease in women vary from country to country. Heart disease death rates for women are lowest in Spain and highest in Scotland, he said. Again, as with men, this variation in rates is not well-understood.
Even more puzzling are the variations in death rates, particularly in the acute phase just after a heart attack, when the patient is hospitalized. In a recent study in the New England Journal of Medicine, (Vaccarino et al. Sex-Based Differences in Early Mortality After Myocardial Infarction. 1999;341:217–225), the study’s author, Viola Vaccarino, MD, and her colleagues found that younger women had an increased risk of death during hospitalization after a myocardial infarction than men of the same age. Previously, it had been thought that women were more likely to die soon after a heart attack because they tended to be older than their male counterparts. However, said Dr Vaccarino, the risk of death was higher among women only before the age of 75. "If a woman gets a heart attack and is in the younger age group, she is in a high-risk group," said Vaccarino, an assistant professor of public health at the Yale School of Public Health in New Haven, Connecticut.
She and her colleagues analyzed data on 384 878 patients between ages 30 and 89, who had been enrolled in the National Registry of Myocardial Infarction 2 between June 1994 and January 1998. Of these, 155 565 were women and 229 313 were men. They found that the overall mortality rate was 16.7% among women and 11.5% for men. However, among patients under 50, the mortality rate for women was more than twice that for men, according to the study.
The study was observational only, she said, and the researchers were unable to determine the various reasons for the variation in death rates. "We definitely need more studies to look at two areas," she said, "one is the possible behavioral/psychosocial factors for women, as well as the possible biological mechanisms that may explain this difference."
Psychosocial factors are often dismissed, she said. However, she was impressed by the numbers of women who did not connect their pain to trouble with their hearts. "They did not even suspect that there could be a problem; one woman said, ‘When I got chest pain, I’d just rest for a little while and the pain would go away.’ She never took any medication or told her doctor."
Also poorly defined are the effects of hormones, especially testosterone, on women, said Dr Martin. The balance between testosterone and estrogen may have an effect, he said; however, it has not been well-studied.
The issue of hormone replacement therapy also arises, especially in the wake of the Heart and Estrogen-progestin Replacement Study (HERS), said Dr Karin Schenck-Gustafson, MD, associate professor of cardiology at the Karolinska Hospital in Stockholm, Sweden. That study, released in the August 19, 1998, issue of the Journal of the American Medical Association, found no lower rates of coronary heart disease in postmenopausal women who took estrogen. This trial of the effects of estrogen replacement in nearly 4000 women who had either had a heart attack or angina found that treatment with estrogen plus progestin did not reduce the rate of coronary heart disease events. The women received either 0.625 mg of conjugated estrogen with meddroxyprogesteroneacetate daily or placebo, in addition to their regular cardiac medications.
Before HERS, Schenck-Gustafson said, epidemiological studies seemed to indicate that women who took estrogen ran a lower risk of heart disease than those who did not. Estrogen replacement therapy is still beneficial in terms of preventing osteoporosis and dealing with the debilitating symptoms of menopause.
Perhaps, she said, the question of what kind of estrogen should be used might be a better question to ask, as well as what dosing might be best to prevent heart disease in women. Studies clearly indicate that estrogen (1) can result in a better lipid profile, (2) has an acute vasodilating effect, and (3) has beneficial effects on carbohydrate metabolism.
The real question, she said, is the effect of hormone replacement therapy on healthy women. That question is being addressed by a study in the United Kingdom, as well as through the Women’s Health Initiative in the United States, which has enrolled 60 000 women.
The answer as to whether hormone replacement therapy improves heart health has not yet been answered definitively. Ongoing studies may help define the issue better, as will tests of other types of estrogens and selective estrogen receptor modulators, which may demonstrate the positive effects of estrogens without the potentially negative effects on the uterus or breasts.
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