Aug. 25, 2009 - Women may have a slightly higher
risk of death than men in the 30 days following an acute coronary
syndrome (ACS; such as heart attack or unstable angina), but this
difference appears attributable to factors such as severity and type of
ACS, clinical differences and severity as determined by angiography,
according to a study in the August 26 issue of the Journal of the
American Medical Association (JAMA).
"Cardiovascular disease is the leading cause of
death in both men and women, accounting for one-third of all deaths.
"Although several studies have shown an improvement of prognosis in women
over time, overall outcomes remain worse for women compared with men,
providing a strong rationale for focusing on the study of sex-based
differences in the outcome of acute coronary syndromes," according to
the article. Previous analyses of the differences in outcomes for men
and women following ACS have reported conflicting results.
Jeffrey S. Berger, M.D., M.S., of the New York
University School of Medicine, New York, and colleagues evaluated the
relationship between sex and 30-day mortality following ACS and analyzed
factors such as clinical classification at the time of ACS and the
severity of angiographic disease. Patients for the study were pooled
from a sample of 11 independent, international, randomized ACS clinical
trials between 1993 and 2006.
Of the 136,247 patients in this analysis, 38,048
(28 percent) were women.
There were 102,004 patients (26 percent women) with
ST-segment elevation myocardial infarction (STEMI; a certain pattern on
an electrocardiogram following a heart attack); 14,466 with non-STEMI (NSTEMI;
29 percent women); and 19,777 with unstable angina (40 percent women).
Women were older and had a higher prevalence of
hypertension, hyperlipidemia, diabetes and heart failure. Men were more
likely to be smokers and had a higher prevalence of prior heart attack
and prior coronary artery bypass graft surgery.
The researchers found that women had a
significantly higher unadjusted 30-day risk of death compared with men
(9.6 percent vs. 5.3 percent). But after multivariable adjustment for
clinical characteristics and clinical presentation, no significant
difference was observed in 30-day mortality.
"Perhaps the most striking findings in our analyses
relate to the examination of mortality according to type of ACS. We
found a significant interaction between sex and type of ACS, such that
30-day mortality risk among women was modestly higher than men only for
those patients presenting with STEMI. In patients with NSTEMI and
unstable angina, women had a lower adjusted 30-day mortality risk than
men. In fact, the strongest finding after full adjustment was lower risk
among women with unstable angina," the authors write.
The researchers also found that overall, women who
underwent catheterization were more likely to have nonobstructive
coronary artery disease and less likely to have multivessel disease
compared with men. The relationship between sex and 30-day mortality was
similar across the levels of angiographic disease severity.
"Our study suggests a better understanding of the
observed sex-based differences. Sex-based differences exist in 30-day
mortality among patients with ACS and vary depending on clinical
presentation.
However, these differences are markedly attenuated
following adjustment for clinical differences and angiographic data. The
attenuation in the difference in mortality suggests that much of the
crude differences are explained by these factors.
This study further highlights the clinical and
angiographic differences among men and women at presentation with ACS.
Understanding and considering these differences may lead to better risk
stratification and treatment of all patients with ACS," the researchers
conclude.
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