THE USEFULNESS OF BONE TURNOVER IN PREDICTING THE RESPONSE TO TRANSDERMAL ESTROGEN THERAPY IN POSTMENOPAUSAL OSTEOPOROSIS

Transdermal estrogen therapy is now an accepted form of treatment for postmenopausal osteoporosis, Ninety postmenopausal osteoporotic women were randomized to receive either transdermal estrogen (0.05 mg/day 17 beta-estradiol) and calcium (n = 45) or calcium alone (n = 45), The s tudy period was 2 years, Bone mineral density (BMD) at the lumbar spin e (by dual-energy X-ray absorptiometry [DXA]) and markers of bone turn over (alkaline phosphatase, osteocalcin, hydroxyproline, pyridinoline cross-links) were assessed at baseline and after 1 and 2 years, In the estrogen-treated group, BMD showed a significant increase (p < 0.001) both after I and 2 years, with a reduction in biochemical markers, To investigate the effectiveness of estrogen treatment of postmenopausal osteoporosis in relation to bone turnover, we also divided the patien ts on the basis of bone turnover, as assessed by measurement of whole body retention (WBR) of Tc-99m-methylene diphosphonate. WBR revealed t hat 26 patients had high bone turnover (HT) and 55 had low bone turnov er (LT), The response to estrogen was greater in the HT patients than in the LT patients; in fact BMD increased by 5.7 and 6.6% in HT patien ts and by 2.6 and 2.7% in LT patients after 1 and 2 Sears, respectivel y, In conclusion, the present study demonstrates that, while the BMD d ecreases in the patients treated with calcium alone, 2-year treatment, vith transdermal estrogen increases axial BMD and that the response to estrogen treatment is influenced by bone turnover, Therefore, the eva luation of bone turnover may be useful to identify those postmenopausa l osteoporotic women who may especially benefit from treatment with es trogen.