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If Women Were Treated
More Like Men, Would Survival After Heart Attack Improve?
Study points to more frequent
use of invasive techniques in men
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March 16, 2010 -- Atlanta, GA – Women
might be more likely to survive a heart attack if they were treated
more like men, with increased use of angioplasty and other invasive
techniques,
according to research presented today at
the American College of Cardiology’s 59th annual scientific session. ACC.10 is
the premier cardiovascular medical meeting, bringing together cardiologists and
cardiovascular specialists to further
advances in cardiovascular medicine.
In a multicenter study of more than 3,000 patients admitted to the hospital for a heart attack, women were
far less likely than men to go to the cardiac catheterization laboratory for angiography or angioplasty, and
about twice as likely to die within a month of having the heart attack. But when a special statistical
method was used to closely match patients by both baseline clinical characteristics and treatments, death
rates were similar among men and women.
“This suggests that we could reduce mortality in female patients by using more invasive procedures,” said
Francois Schiele, M.D., professor of cardiology and cardiology chief at the University Hospital of
Besancon, France. “When there are no clear contraindications, women should be
treated with all
recommended strategies, including invasive strategies.”
Several previous studies have suggested that
women have a higher risk of death after a heart attack than men, but
the reasons have been unclear. Possible explanations include biological
differences in the
atherosclerotic process, differences in the structure and physiology of women’s
arteries, and clinical differences when the heart attack occurs (women tend to
be older, have poorer overall health, and wait
longer to seek medical care). But there are also substantial differences in the
therapies women receive
once they arrive at the hospital.
“The main question we tried to answer with this study was whether the difference in mortality between
women and men after a heart attack is explained by differences in management,” Schiele
said.
For the study, researchers analyzed data from a regional registry that included all patients treated for a
heart attack between January 2006 and December 2007. Of the 3,510 patients in the study, 1,119 (32
percent) were women. A comparison of raw data showed that women were, on average, nine years older
than men, had more health problems, received fewer effective treatments for heart attack, and were nearly
twice as likely to die, both during the initial hospital stay (9.7 percent vs. 5.0 percent) and over the
following month (12.4 percent vs. 7.0 percent).
Researchers used a statistical method known as propensity score matching, which attempts to reduce the
bias of treatment-effect estimates from observational studies, to create pairs of men and women closely
matched according to baseline characteristics (by up to 8 digits of their propensity scores). This created a
population of 1,298 patients composed of 649 pairs. A second population of matched pairs was created by
taking into account not only baseline characteristics but also the treatments and strategies actually used
for each patient. This population of 584 pairs represented 1,168 patients. (Because the procedure is very
precise, not all patients could be matched.)
When the researchers analyzed data from the first 649 pairs, they found that despite very similar clinical
characteristics, men were 57 percent more likely than women to undergo coronary angiography, a
diagnostic procedure in which dye is injected into the arteries of the heart to enable visualization of any
blockages by X-ray imaging. Among patients who had an especially serious form of heart attack known
as ST-elevation myocardial infarction, men were far more likely than women to receive therapy to reopen
the blocked artery, whether by clot-busting drugs (used 72 percent more often in men) or by
angioplasty (used 24 percent more often in men). The death rate during the initial hospital stay was 48
percent lower in men than in women, and the death rate within 30 days of the heart attack was about 30
percent lower in men, although this last finding was of borderline statistical significance.
When researchers analyzed the second set of 584 pairs, matched on both clinical characteristics and
treatments, there were no longer any statistically significant differences in mortality between genders,
either in-hospital or at 30 days.
“We need to improve outcomes in women who have a heart attack,” Schiele said. “There
is a difference in outcomes between women and men, and we need to know what it
stems from and what we can do about
it.”
The data registry in this study is supported by a research
association (Association
Franc Comtoise d’Aide
à la Recherche en Cardiologie) and by unrestricted grants from GlaxoSmithKline,
Novartis, Sanofi- Aventis and Servier.
Source: American College of Cardiology
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