Transition to raloxifene with and without low-dose estrogen therapy in postmenopausal women: effects on serum lipids and fibrinogen - a pilot study

Abstract

Objective: To compare the effects of transferring from low-dose transdermal estrogen to raloxifene (RLX), with a phase of alternate-day RLX therapy with or without low-dose transdermal estrogen, on serum lipids and fibrinogen in postmenopausal women previously administered estrogen plus progestogen therapy. Methods: Sixty postmenopausal women (mean age 55 years) were randomized to one of two treatment groups: RLX + low-dose transdermal estrogen (RLX + E) or RLX + placebo. The study consisted of four 8-week phases: phase I (all subjects low-dose transdermal estrogen 25 μg/day), phase II (double-blind RLX 60 mg every 2nd day in combination with either low-dose transdermal estrogen or placebo), phase III (all subjects RLX 60 mg every 2nd day + placebo) and phase IV (all subjects RLX 60 mg/day + placebo). Results: No significant differences existed between groups for baseline measurements prior to phase I. In phase I, for all subjects combined, total cholesterol and low-density lipoprotein cholesterol both showed a significant increase (median increase of 0.2 mmol/l, p = 0.008 and 0.4 mmol/l, p< 0.001, respectively), while triglycerides decreased significantly (median decrease of 0.2 mmol/l, p< 0.001). For the primary analysis (phase II to phase IV), the mean change from baseline observations showed no significant differences between the therapy groups for serum lipids, fibrinogen, vital signs or weight. In the comparison phase (phase II), changes in serum lipids, fibrinogen, vital signs and weight were not significantly different between groups. Conclusion: Gradual conversion to RLX from low-dose transdermal estrogen, with a phase of alternate-day RLX therapy with or without low-dose transdermal estrogen, does not have any effect on the serum lipid profile or fibrinogen level.