Raloxifene lowers serum lipoprotein(A) in healthy postmenopausal women: a randomized, double-blind, placebo-controlled comparison with conjugated equine estrogens.

OBJECTIVE: Long-term postmenopausal estrogen replacement therapy lowers the risk of osteoporotic fractures and coronary artery disease but increases the risk of endometrial cancer and probably breast cancer. Raloxifene, a nonsteroidal estrogen receptor ligand, seems to have a tissue-specific antiestrogenic action on endometrium and breast and the desired estrogenic action on bone and lipid metabolism. The purpose of this study was to investigate the effects of 24-month treatment with orally administered raloxifene in two doses (60 mg and 150 mg daily) and conjugated equine estrogens in a standard oral dose (0.625 mg daily) on serum lipoprotein(a) [Lp(a)], an independent risk factor for coronary artery disease, in healthy postmenopausal women who had undergone hysterectomy. DESIGN: A randomized, double-blind, placebo-controlled study was performed with 56 women. RESULTS: In the placebo group serum Lp(a) levels did not change throughout the study. After 6 months, serum Lp(a) was significantly reduced versus baseline in the raloxifene 150 (-17%; p = 0.003) and conjugated equine estrogens (-26%; p = 0.003) groups, but this reduction was significantly different from placebo only in the conjugated equine estrogens group. At 12 and 24 months, serum Lp(a) levels were significantly lowered versus baseline in all active treatment groups. However, these reductions were significantly different from placebo only in the raloxifene 150 and conjugated equine estrogens groups. After 24 months, serum Lp(a) was reduced versus baseline with 30% (p = 0.001) in the raloxifene 150 group and 35% (p = 0.001) in the conjugated equine estrogens group. CONCLUSIONS: Long term raloxifene treatment significantly lowers serum Lp(a) levels in postmenopausal women and thus might reduce the risk of coronary artery disease.