Double-blind, placebo-controlled study of the effects of tibolone on bone mineral density in postmenopausal osteoporotic women with and without previous fractures

Abstract

A 2-year placebo-controlled, randomized, two-center prospective study was carried out to assess the effects of tibolone (Org OD14, Livial) on trabecular and cortical bone mass and bone biochemistry parameters in elderly postmenopausal women with and without previous fractures. In total, 107 subjects, 71 with fractures and 36 without fractures, were randomized to tibolone (n = 64) or placebo (n = 43). Their mean age was 63.1 years. Bone mineral density (BMD) (g/cm2) was assessed at baseline and every 6 months for 2 years by dual-energy X-ray absorptiometry (DXA). Mean baseline values were 0.79 and 0.80 for the lumbar spine in the tibolone and placebo groups, respectively, and for the femoral neck 0.64 in both groups. Serum and urinary bone biochemistry parameters were measured concurrently. An analysis of variance (ANOVA) model including center and group was applied. The completers' group was the primary subset for the analysis; the intention-to-treat (ITT) group was also analyzed. Results are expressed as the percentage change at 24 months and the annual rate of change percentage year. The tibolone group showed an overall mean increase (vs. placebo) in BMD at the lumbar spine of 7.2% (p < 0.001) and for the femoral neck 2.6% (p < 0.001). In subjects with previous fractures increases were 6.0% and 4.0% for the lumbar spine and femoral neck, while in those with no fractures, respective changes were 8.9% and 1.1%. Overall changes in the placebo group were 0.9% and -1.6% for the lumbar spine and femoral neck, respectively. A significant fall in bone biochemistry parameters showed that tibolone inhibits osteoclastic activity. In conclusion we have found that tibolone 2.5 mg induces significant increases of trabecular and cortical bone mass in elderly postmenopausal osteoporotic women with and without previous fractures.