“Microdose” Transdermal Estradiol: As Effective as Raloxifene in Preventing Bone Loss?

Results of the Women's Health Initiative raised questions about the role of estrogen therapy in postmenopausal women. In this manufacturer-supported double-blind study of interventions to prevent bone loss, investigators randomized 340 postmenopausal women (mean age, 66) to receive either daily transdermal “microdose” 17β-estradiol (E2, Menostar; 0.014 mg) or daily oral raloxifene (60 mg) for 2 years. All women had intact uteri and lumbar spine osteopenia.

Lumbar spine bone-mineral density (BMD) increased from baseline by 2.4% with E2 and by 3.0% with raloxifene; about 80% of women in both groups had no bone loss in the lumbar spine. Total hip BMD increased significantly more in those taking raloxifene than in those taking E2 (1.8% vs. 0.4%)…