Sex differences in mortality after myocardial infarction. Is there evidence for an increased risk for women?

A number of studies have indicated that women who have a myocardial infarction have higher mortality rates than men. The purpose of the present study was to review the literature on sex differences in mortality after myocardial infarction to determine whether female sex is independently associated with lower survival.

Reports were identified mainly through a MEDLINE search of the English-language literature from January 1966 through June 1994. Studies included were those comparing mortality after myocardial infarction between men and women, controlling at least for age and with more than 30 outcome events. After duplicate patient series were eliminated, 27 reports were included in our review. Crude rates were higher in women than in men during the early phase (in-hospital or first month), but control for age alone or in combination with other factors reduced sex differences in almost all studies. Unadjusted mortality rates among the survivors of the early phase were similar for men and women in most studies, and control for age and other factors resulted in an increased survival rate in women compared with men in several investigations, particularly those with a follow-up of > 1 year.

Much of the increased early mortality after myocardial infarction in women is explained by the older age and more unfavorable risk characteristics of the women. In the long run, when differences in age and other risk factors are controlled for, women tend to have an improved survival compared with men.