A 2-year, randomized, comparative, placebo-controlled study on the effects of raloxifene on lipoprotein(a) and homocysteine

Objectives: Lipoprotein(a) (Lp(a)) and homocysteine (Hcy) are independent cardiovascular risk factors, which have been shown to be lowered by hormone replacement therapy (HRT). In this 2-year study, the long-term effects of raloxifene (Rlx) in two doses, on Lp(a) and Hcy, were studied and compared with the effects of continuously combined hormone replacement therapy (ccHRT). Methods: In a prospective, randomized, double-blind, placebo-controlled 2-year study, 95 healthy, non-hysterectomized, early postmenopausal women, received daily either oral Rlx 60 mg (N = 24) or 150 mg (N = 23), ccHRT (conjugated equine estrogens 0.625 mg plus medroxyprogesterone acetate 2.5 mg; N = 24) or placebo (N = 24). Fasting serum Lp(a) and plasma Hcy concentrations were measured at baseline and at 6, 12 and 24 months. Results: The mean individual changes compared to baseline after 24 months were for Lp(a): Rlx 60: - 5%, Rlx 150: - 7%, ccHRT: - 34%, placebo: + 1% and for Hcy: Rlx 60: - 3%, Rlx 150: - 4%, ccHRT: - 4%, placebo: + 6%. ANCOVA was significant for Lp(a) under ccHRT versus placebo (P = 0.001) and for Lp(a) under ccHRT versus each of the two Rlx groups (P < 0.05). Conclusions: Long-term treatment with Rlx was not as effective as ccHRT in lowering Lp(a). Although not significant and without an obvious dose-related response, the Hcy values showed the same trend for each treatment arm, which is in line with data reported earlier.