AMINOHEXANE BISPHOSPHONATE SUPPRESSES BONE TURNOVER IN POSTMENOPAUSALWOMEN MORE RAPIDLY THAN ESTROGEN-GESTAGEN THERAPY

Although animal studies suggest that there may be major differences be tween the effects of bisphosphonates and ovarian hormones on skeletal metabolism, whether this also holds for their actions in patients is u nknown. To address this question, we compared the effects of 12 weeks treatment with HRT on bone turnover markers in osteopenic postmenopaus al women with those of an amino-bisphosphonate. Women within 15 yr of the menopause, with a lumbar and/or femoral neck bone mineral density 1 S.D. below the predicted value, received either oestradiol valerate 2 mg and dydrogesterone 5 mg (E/D; n = 16) or aminohexane bisphosphona te 400 mg (AHBP; n = 9). Urine and serum samples were collected on two separate occasions before starting treatment, and 1, 2, 4, 8 and 12 w eeks afterwards. To assess bone resorption, we measured the urinary de oxypyridinoline/creatinine ratio (DPD/crea), while serum alkaline phos phatase (ALP), osteocalcin and C-terminal propeptide of type I collage n (CICP) were analysed to assess bone formation. Repeated measures ana lysis of variance revealed a highly significant decrease in DPD/crea o ver the treatment period. Furthermore, this pattern of response differ ed significantly between the two treatment groups, since DPD/crea was maximally suppressed within 2 weeks of starting AHBP, while E/D showed little decrease until 8 weeks. AHBP was also found to suppress ALP, o steocalcin and CICP more rapidly than E/D, the former reducing these m arkers by 8 weeks, while E/D caused little inhibition even by 12 weeks . We conclude that, in the doses used in this study, AHBP appears to s uppress bone turnover significantly more rapidly than E/D, suggesting that clinically important differences may exist in the effects of bisp hosphonates and ovarian hormones on bone metabolism.