Cholesterol-lowering drugs are just as effective at preventing heart problems in men and women who have already had a heart attack or stroke, according to a new review of the evidence.
However, the combination of data from 11 smaller trials didn't show a clear benefit when it came to warding off strokes or deaths from any cause in women.
Although statins are widely used for so-called secondary prevention - to prevent repeat strokes and heart attacks in people who have already had one - some analyses have questioned whether they work as well in women as in men, said Dr. Jose Gutierrez from Columbia University in New York.
To better get at that question, he and his colleagues consulted previous trials in which both men and women at risk of a second heart attack or stroke were randomly assigned to a statin or a drug-free placebo pill.
Those studies included a combined 43,000 people and lasted anywhere from four months to more than six years. The statins tested in the studies included simvastatin (marketed as Zocor), pravastatin (Pravachol) and atorvastatin (Lipitor).
Overall, the findings showed, both men and women assigned to statins were 18 to 19 percent less likely to have one of a combination of any cardiovascular problems, including heart attacks, strokes and deaths related to heart disease.
For example, about seven percent of both men and women on statins had a heart attack - either fatal or not - compared to ten percent of participants on placebos.
Men taking statins also had a 19 percent lower risk of strokes in particular and a 21 percent reduced chance of dying from any cause than those in the placebo group.
The same trend held up in women - but the effect was smaller, and the difference between the statin and placebo groups could have been due to chance, the researchers reported Monday in the Archives of Internal Medicine.
Gutierrez and his colleagues noted that both men and women had similar changes in their cholesterol while on the drugs, including a 26-point drop in total cholesterol in the statin group versus a three- to six-point difference among those taking placebos.
One limitation, the researchers noted, is women only made up about one-fifth of all participants in the studies combined - so it's possible there just weren't enough of them to show the same effect of statins on strokes and deaths that was seen in men.
There are other possible explanations if women turn out to really not get as much benefit from statins, Gutierrez said, such as the effect of hormonal differences.
"Another explanation could be the health disparity in women, and if they are sicker, probably we don't see as much benefit," he told Reuters Health.
Gutierrez noted that women in the studies his team evaluated were less likely to be taking aspirin and other potentially risk-reducing medications than men.
Side effects of statins include muscle and joint aches, nausea and constipation. They can run anywhere from $11 to over $200 per month.
Not the end-all, be-all
Despite some lingering questions, the researchers said their new analysis "supports the use of statins in women" who have already had a stroke or heart problems.
Dr. Dennis Ko, a cardiologist at the Schulich Heart Center at Sunnybrook Health Sciences Center in Toronto, who wasn't involved in the new analysis, agreed.
"The overall benefit - it's pretty consistent for men and women," he told Reuters Health.
The analysis "still favors women to get statin medication (for secondary prevention) and not forgo it because they didn't see a mortality difference," Ko said. "I think everything goes in favor of statin therapy."
But the drugs aren't the end-all, be-all for heart health, researchers said.
"Despite statins, cardiovascular events continue occurring," Gutierrez said. "They still happen regardless of what we do. So maybe besides statins, we should also concentrate on other factors that affect cardiovascular disease, such as hypertension, diabetes and smoking cessation."