Combination of Intermittent Cyclical Etidronate and Hormone Replacement Therapy for Postmenopausal Non-Responders to Estrogen

Abstract

To investigate whether the addition of etidronate to conventional hormone replacement therapy (HRT) is effective against bone loss in postmenopausal women whose lumbar bone mineral density (BMD) cannot be maintained by HRT. Single-centre, placebo-controlled randomised study. Among 1138 patients on conventional HRT, 30 postmenopausal women were considered to be non-responders to estrogen, since their BMDs continued to decrease by more than 1% per year in spite of the HRT. The BMD of all the included patients was less than 70% of the young adult mean. PATIENTS were randomly divided into two groups: group A (n = 15) treated with conventional HRT and placebo, and group B (n = 15) treated with combined intermittent cyclical etidronate therapy (ICT-etidronate) and conventional HRT. Measurement of lumbar BMD was performed at baseline and at 6 and 12 months using dual energy x-ray absorptiometry (DEXA). Biochemical markers of bone resorption and formation were also measured during the visits. ICT-etidronate combined with HRT increased the lumbar BMD at 6 months (p < 0.05) and 12 months (p < 0.05) compared with baseline. Lumbar BMDs of the combined treatment group were significantly increased at 12 months (p < 0.05) compared with the HRT-only group. Bone resorption was suppressed by combined therapy at 6 months (p < 0.05). Bone formation did not change in either group. ICT-etidronate combined with HRT seems to be effective in preventing loss of BMD in postmenopausal women who do not respond to estrogen, and may be useful in preventing fractures in this group.