Aspirin benefits vary for men, women
In 2003, cardiologist Niecs Goldberg wrote a book entitled, “Women Are Not Small Men.” Dr. Goldberg pointed out that, until recently, all the research, knowledge and treatments for heart disease were based on studies done on men. And the assumption was that women were just men who weighed less. Women and men, they thought, behaved just the same when it came to heart disease.
But the fact is we’re not the same in much of anything, especially when it comes to heart disease. Our hearts are smaller and our physiology is different. We develop our heart disease later than men – typically 10 years later. When suffering from a heart attack, we often have “atypical” symptoms – back pain and jaw pain, for example, rather than the “typical” (male) symptoms of crushing chest pain and profuse sweating.
If our symptoms are different, if the age we get our heart disease is different, is our response to treatment and prevention strategies different as well?
A study this month in the New England Journal of Medicine takes on this issue. Researchers looked at the effectiveness of low-dose aspirin in the primary prevention of heart attacks and strokes in women. In other words, the women who were studied had no previous history of heart disease or stroke.
The authors found only five randomized, controlled studies (remember, those are the best kind) that evaluated aspirin in the primary prevention of cardiovascular disease, and three of those studies evaluated only men. Altogether, these studies showed a 32 percent reduction in heart attacks, but do we know if that protective effect was as good in women as in men?
To find out, researchers evaluated nearly 40,000 women in the Women’s Health Study. The women were at least 45 years old, and they were followed for 10 years. They were divided into two groups: one group took 100 mg of aspirin every other day for the 10 years; the other group took a placebo. The researchers monitored the two groups for non-fatal heart attack, non-fatal stroke, and death from cardiovascular causes.
During the ten-year follow-up, there were 477 major cardiovascular events in the aspirin group, and 522 in the placebo group – not much difference. There was no statistical difference in the number of fatal or non-fatal heart attacks. Not much good news there. But aspirin did reduce the risk of ischemic stroke (due to a blockage of blood flow to part of the brain), the more common type of stroke, by 24 percent.
When the researchers looked at a particular subset of women, those who were 65 or older at the start of the study, the benefits of aspirin were more apparent. Ischemic strokes were reduced by 30 percent. This group also had 34 percent fewer heart attacks.
Studies show that low dose aspirin clearly reduces the risk of stroke and heart attacks in both men and women who have already had a stroke or heart attack – that’s secondary prevention. But this study, and further analysis of the data on women in other primary prevention studies, showed benefits for women that were the exact opposite of those for men: Aspirin reduced the risk of stroke in women, but not in men. Aspirin reduced the risk of heart attacks in men, but not in women (except for that subset of 65 and older.)
This study is important for us women for at least two reasons. First, women, as compared to men, have relatively more strokes than heart attacks. So these findings support the use of low dose aspirin for women to reduce strokes, just as other studies support its use to reduce the risk of heart attacks in men. Second, it underscores the importance of studying women, as well as men, in major treatment trials.
Because, as Dr. Goldberg says, when it comes to heart disease, women are not small men. The question for researchers is, for what other diseases is this the case? Inquiring minds want to know.