Objective: To identify the optimal dosage of 17beta-estradiol gel + oral progestin for preventing bone loss in postmenopausal Chinese women.
Methods: A 3-year open label, randomized, prospective clinical trial was conducted. Sixty healthy women who had been postmenopausal for 1 to 5 years were recruited and divided into following 4 groups: group 1, percutaneous gel 17beta-estradiol (E(2)) 1.5 mg/d plus micronized progesterone (MP) 100 mg/d; group 2, percutaneous gel 17beta-estradiol (E(2)) 1.5 mg/d plus medroxyprogesterone acetate (MPA) 2 mg/d; group 3, percutaneous gel 17beta-estradiol (E(2)) 0.75 mg/d plus micronized progesterone (MP) 100 mg/d; and group 4, percutaneous gel 17beta-estradiol (E(2)) 0.75 mg/d plus medroxyprogesterone acetate (MPA) 2 mg/d. Estrogen and progestin were given continuously for 25 days per month. Bone mineral density (BMD) was measured using quantitative computed tomography (QCT) for trabecular bone of L2-5 and dual energy X-ray absorptiometry (DEXA) for L2-4 and hip 5 times during the trial at baseline and at the 6-, 12-, 18-, 24- and 36-month visits.
Results: Fifty-nine patients (98.3%, 59/60) stayed in the study for 1 year, 56 patients (93.3%, 56/60) for 2 years, and 51 (85%, 51/50) for 3 years. On average, menopausal symptoms were relieved by 80% after 6 months of treatment. By the 24th month, the mean increase in BMD ranged from 4.3% to 7.5% in trabecular bone; and by the 36th month, it ranged from 4.2% to 6.2% in L2-4 and 1.61% to 3.77% in the neck. There were significant difference after treatment (P < 0.05). Among the four groups, no significant difference (P > 0.05) was found in improvement of symptoms, levels of bone markers or BMD.
Conclusion: A daily dose of estradiol gel, either 0.75 mg or 1.5 mg, is effective in preventing early postmenopausal bone loss and relieving menopausal symptoms. After 3-year treatment, spinal BMD could increase steadily, so does hip BMD, especially in the first 2 years.