A randomized study of tibolone on bone mineral density in osteoporotic postmenopausal women with previous fractures

Objective: To investigate the effects of tibolone on trabecular and cortical bone mineral density and on indices of calcium metabolism in postmenopausal women with previous fractures. Methods: In a 2-year, randomized, double-blind, placebo-controlled, bicenter study, 45 women were treated with tibolone and 43 with placebo. All subjects received 800 mg of calcium daily. Trabecular bone mineral density of lumbar spine (L1 to L4) and cortical bone mass at the femoral neck were assessed by dual energy x-ray absorptiometry at baseline and at 6-month intervals. Serum and urinary bone biochemistry variables were also assessed. Results: After 2 years, subjects in the tibolone group gained 6.9% bone mass at lumbar spine and 4.5% at femoral neck, and respective increases from baseline in the placebo group were 2.7% and 1.4%. Tibolone-treated patients gained statistically significantly more bone mass than placebo-treated patients in the spine and femur. Urinary calcium: creatinine and hydroxyproline:creatinine ratios, as well as serum alkaline phosphatase and phosphate levels, were significantly reduced with tibolone compared with placebo. Conclusion: Tibolone induced a significant increase in trabecular (lumbar spine) and cortical (femoral neck) bone mass in postmenopausal osteoporotic women compared to placebo, suggesting its potential to treat postmenopausal osteoporosis. (Obstet Gynecol 1998;92:574-9. (C) 1998 by The American College of Obstetricians and Gynecologists.).