Study shows raloxifene does not raise risk of heart attack or stroke
The osteoporosis drug raloxifene (Evista) is a form of hormone replacement therapy prescribed for postmenopausal women to prevent bone loss and rebuild lost bone density. The drug has also been shown to reduce risk factors for heart disease and stroke—for example it lowers LDL (bad) cholesterol levels. However, recent studies have suggested that hormone replacement therapy may increase the risk of early cardiovascular events, such as heart attack and stroke, in postmenopausal women with cardiovascular disease. Research recently published in the Journal of the American Medical Association suggests that raloxifene does not raise the risk of heart attack and stroke in postmenopausal women. In fact, the results suggest it may reduce this risk in postmenopausal women at high risk of cardiovascular disease.
About the study
Researchers at Eli Lilly and Company, the manufacturer of raloxifene, analyzed data from the Multiple Outcomes of Raloxifene Evaluation (MORE) study, which was conducted between November 1994 and September 1999. The MORE study, also sponsored by Lilly, was designed to assess raloxifene's effect on bone mineral density and spinal fractures in 7705 postmenopausal women with osteoporosis. As part of this study, women's cholesterol levels were checked, and heart attack and stroke were reported as adverse events. For this reason, the Lilly researchers decided to analyze the data from the MORE study a second time to see if cardiovascular events were more common in women taking raloxifene than in women taking a placebo (inactive pill). Cardiovascular events included heart attack, angina, stroke, transient ischemic attack (TIA), and medical procedures to prevent heart attack and stroke.
Women in the MORE study had been randomly assigned to receive either 60 mg per day of raloxifene, 120 mg per day of raloxifene, or a placebo. In addition, at the start of the study they provided information about reproductive history, prior postmenopausal hormone use, education, ethnicity, smoking, alcohol consumption, and other risk factors for heart disease and stroke. Although the study included women from 25 countries, more than 95% of the women were white. Women were excluded from the study if they had a stroke or venous thromboembolic disease during the past ten years.
In the secondary analysis, researchers also assessed each woman's risk factors for cardiovascular events in order to determine if raloxifene's effects differed in women at higher risk. Of 7705 women in the study, 1035 were determined to be at increased risk of cardiovascular events; 202 of these women had a history of an acute coronary event or medical procedure.
Women taking raloxifene were no more likely to have a cardiovascular event than women taking placebo. In fact, among women at higher risk of cardiovascular events, those taking raloxifene were 40% less likely to have a cardiovascular event than those taking placebo.
These findings were true for the entire four years of the study, as well as for the first year alone. This is important because hormone replacement therapy is suspected of increasing the risk of cardiovascular events in the early months after drug treatment begins.
There are several limitations to this study, however. First, the vast majority of the women were white, so it is not clear whether these results apply to women of other racial and ethnic groups. Second, approximately 25% of the participants did not complete the study for various reasons. Third, because the original MORE study was designed to assess raloxifene's bone-building ability, there were relatively few women in the study who had cardiovascular disease or increased risk of cardiovascular events. Larger studies of raloxifene use in high-risk women and women with cardiovascular disease are needed to confirm these results. Finally, cardiovascular events were self-reported by the study participants, and in many cases, complete medical records of the events were not available.
How does this affect you?
Is it safe for postmenopausal women to take raloxifene for osteoporosis? This study provides some reassurance that raloxifene is not likely to increase the risk of heart attack and stroke in postmenopausal women, regardless of whether they have cardiovascular disease. However, other studies of hormone replacement therapies (of which raloxifene is one) have yielded contradictory results. If you have osteoporosis or are at risk of osteoporosis, talk with your health care provider about your medication and therapy options.
Will taking raloxifene protect against heart attack and stroke? Although these findings provide some evidence that it may, the authors of this study caution that more research is needed to determine if raloxifene does in fact reduce the risk of heart attack and stroke.
Barrett-Connor E, et al. Raloxifene and cardiovascular events in osteoporotic postmenopausal women. Four-year results from the MORE (Multiple Outcomes of Raloxifene Evaluation) Randomized Trial.
Journal of the American Medical Association . February 20, 2002;287(7):847-857.
Last reviewed Feb 22, 2002 by ]]>Richard Glickman-Simon, MD]]>
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