Continuous, combined hormone replacement: randomized comparison of transdermal and oral preparations

OBJECTIVE: To compare two new transdermal, continuous, combined formulations and an oral regimen of hormone replacement therapy (HRT) with respect to endometrial hyperplasia, bleeding patterns, and climacteric symptoms in postmenopausal women. METHODS: This was a randomized, open, parallel-group trial during 1 year in 441 postmenopausal women who received either a 10-cm2 patch of 0.025 mg estradiol (E2) and 0.125 mg norethisterone acetate, a 20-cm2 patch of 0.05 mg E2 and 0.25 mg norethisterone acetate twice weekly, or tablets of 2 mg E2 and 1 mg norethisterone acetate once daily. The efficacy variables were frequency of endometrial hyperplasia after 1 year of treatment, number of bleeding and spotting days from the fourth to sixth treatment months, relief of climacteric symptoms, and tolerability. RESULTS: The frequency of endometrial hyperplasia was no more than 2% after 1 year of treatment in all groups. One case of simple hyperplasia was detected among the women treated with 10-cm2 patches and two among those treated with oral HRT. From the fourth to sixth treatment months, amenorrhea occurred in 73%, 47%, and 66% of the women in the 10-cm2, 20-cm2, and oral HRT groups, respectively. The 10-cm2 patches and oral treatment were associated with fewer bleeding days than were the 20-cm2 patches (P<.001). During the last 3 months of the treatment year, amenorrhea was found in 100 subjects (86%) for 10-cm2 patches, 61 (65%) for 20-cm2 patches, and in 85 (79%) for oral HRT. All treatments alleviated the climacteric symptoms to a comparable extent. CONCLUSION: In postmenopausal women, 10-cm2 patches relieved climacteric symptoms and prevented endometrial hyperplasia at least as effectively as oral HRT. Amenorrhea was induced early in a high percentage of women using 10-cm2 patches and oral HRT, and these therapies seemed to be convenient, effective, and safe for estrogen deficiency symptoms in postmenopausal women.