A paper published online by the journal Circulation on 8 December 2008 concluded that, while men and women have a similar in-hospital death rate following acute myocardial infarction, women with STEMI had an adjusted mortality rate almost twice as high as men (10.2% versus 5.5%). These differences were associated with a lower likelihood of reperfusion therapy in women. The paper was widely reported in the press, with suggestions of disparity in care and outcome after AMI.
This study is one of many undertaken in the past 20 years on gender differences in the management of acute coronary events. Many, like this latest study, have found that women are treated less intensively in the acute phase. However, after adjustment for age, co-morbidity and severity of disease, some of these disparities have been found to disappear. Similarly, many studies have found gender differences in short-term survival rates after AMI, but such differences have not always persisted in the long term.
In Europe results from a Swedish cohort study of 53,781 subjects (of whom 37 per cent were women) also showed that overall women were less intensively treated than men, but, in cases of non-STEMI, had a better long-term prognosis than men.
Commenting for the ESC on the STEMI results in the Circulation paper, Professor Eva Swahn (University Hospital, Linköping, Sweden), who has conducted gender studies in acute coronary syndrome patients, said: "We are not surprised. We found similar results in our Swedish cohort study."
Although the incidence of AMI is low in both sexes, especially in premenopausal women, the view persists - mistakenly - that women don't have the same coronary symptoms as men. "This is a myth," says Professor Swahn. "The classical symptoms of AMI are the same for women as for men." However, this mistaken belief may explain why reperfusion therapy is not started as quickly in women as in men - because women interpret their symptoms differently from men and may not summon help soon enough.
While there are some recurring patterns in the studies - less intensive treatment in women, lower survival rates in female STEMI patients - much of the explanation for the disparities remains unknown. Definite answers about medication, invasive or non-invasive treatment, and survival will only be derived from studies powered to draw significant conclusions in both men and women in the same prospective cohort. And the optimal treatment recommendations for men and women respectively will only be resolved by inclusion of sufficient numbers of both women and men in future clinical trials.