Monitoring bone effect of transdermal hormone replacement therapy by ultrasound investigation at the phalanx: a four-year follow-up study.

Objective: A controlled 4-year follow-up study was conducted on a population composed of 112 healthy early postmenopausal women to evaluate the ability of ultrasound technology in detecting the effects of hormone replacement therapy (HRT) on bone. At the end of the study, 47 untreated and 25 treated women had been evaluated. Cyclic sequential estrogen/progestogen therapy, 50 microg/day of transdermal 17beta-estradiol (Rotta Research Laboratorium) plus 5 mg/day of medrogestone (Wyeth-Ayerst) was used.

Design: Ultrasound transmission through the distal metaphysis of hand phalanxes was measured by DBM Sonic. Beside amplitude-dependent speed of sound (AD-SoS), three new parameters could be calculated: pure speed of sound (pSOS), bone transmission time (BTT), and ultrasound bone profile index (UBPI). Ultrasound measurements were taken at baseline and after 1, 2, and 4 years.

Results: Among untreated women a significant decrease of all ultrasound parameters was observed at follow-up measurements. In the HRT-treated group we observed a significant increase of AD-SoS, pSoS, and BTT. We qualified as "responders" women in the treated group for whom AD-SoS, pSoS, and BTT increased by more than 2.77 times the coefficient of variation of the measurement, i.e., 95% variability. Women in the treated group were identified as responders at 4 years of follow-up by AD-SoS (56%), pSOS (56%), and BTT (60%). Ultrasound bone profile index declined in both groups, although to a lower extent among HRT-treated subjects.

Conclusions: The 4-year data confirm the results obtained at 1 and 2 years of follow-up. This study demonstrates that bone tissue investigation by ultrasound at the phalanx can be used to monitor the effect of HRT, and thus it should be considered a potential technology for the management of menopause by gynecologists.