Safety and adverse effects associated with raloxifene: multiple outcomes of raloxifene evaluation.

OBJECTIVE

To examine the effect of raloxifene on major adverse events that occur with postmenopausal estrogen therapy or tamoxifen.

METHODS

The Multiple Outcomes of Raloxifene Evaluation, a multicenter, randomized, double-blind trial, enrolled 7,705 postmenopausal women with osteoporosis. Women were randomly assigned to raloxifene 60 mg/d or 120 mg/d or placebo. Outcomes included venous thromboembolism, cataracts, gallbladder disease, and endometrial hyperplasia or cancer.

RESULTS

During a mean follow-up of 3.3 years, raloxifene was associated with an increased risk for venous thromboembolism (relative risk [RR] 2.1; 95% confidence interval [CI] 1.2-3.8). The excess event rate was 1.8 per 1,000 woman-years (95% CI -0.5-4.1), and the number needed to treat to cause 1 event was 170 (95% CI 100-582) over 3.3 years. Risk in the raloxifene group was higher than in the placebo group for the first 2 years, but decreased to about the same rate as in the placebo group thereafter. Raloxifene did not increase risk for cataracts (RR 0.9; 95% CI 0.8-1.1), gallbladder disease (RR 1.0; 95% CI 0.7-1.3), endometrial hyperplasia (RR 1.3; 95% CI 0.4-5.1), or endometrial cancer (RR 0.9; 95% CI 0.3-2.7).

CONCLUSION

Raloxifene was associated with an increased risk for venous thromboembolism, but there was no increased risk for cataracts, gallbladder disease, endometrial hyperplasia, or endometrial cancer.

LEVEL OF EVIDENCE: I