NEW YORK (Reuters Health) – Treatment with the nonsteroidal selective estrogen receptor modulator raloxifene may heighten the risk of venous thromboembolic events and stroke deaths in postmenopausal women at increased risk of coronary heart disease, according to study published in the January issue of Stroke.

Thus, lead author Dr. Lori Mosca and her associates advise: “Decisions about the use of raloxifene to prevent or treat osteoporosis or to prevent invasive breast cancer in postmenopausal women should consider the absolute risk of stroke and venous thromboembolic events based on individual characteristics, including cigarette smoking and history of venous thromboembolism prolonged immobilization.”

To identify individual risk factors that might predict the outcome of raloxifene treatment, the researchers conducted a secondary end point analysis of the international Raloxifene Use for The Heart (RUTH) trial. It included more than 10,000 postmenopausal women with or at increased risk of coronary heart disease, randomly assigned to raloxifene (Evista, Eli Lilly and Company) 60 mg/d or placebo.

Their analysis showed that raloxifene was associated with significantly higher risks of stroke deaths (hazard ratio 1.49; absolute risk increase 0.07 per 100 women treated for 1 year; p = 0.05) and venous thromboembolic events (HR 1.44; absolute risk increase 0.12 per 100 women, p = 0.02).

However, overall mortality and the incidence of stroke did not differ between the groups, Dr. Mosca, at Columbia University in New York, and her team report. Moreover, no specific demographic or clinical risk factor could be identified, other than a statistically nonsignificant trend toward increased stroke risk among smokers.

Although these results are plausible based on similar findings for hormone therapy or other estrogen receptor modulators, the authors also acknowledge that the observed risks may be “spurious and due to the multiple number of analyses that was performed.”

They advise clinicians to evaluate the excess risk of fatal stroke and venous thromboembolic events “in the context of clinical trial results documenting a reduced risk of invasive breast cancer (absolute risk reduction 0.12 per 100) and clinical vertebral fracture (absolute risk reduction 0.13 per 100) in the RUTH population.”

Reference:
Stroke 2009;40:147-155.