Randomized trial comparing low-dose hormone replacement therapy and HRT plus 1α-OH-vitamin D3 (alfacalcidol) for treatment of postmenopausal bone loss

We conducted a prospective, randomized, multicenter, open-label 2-year trial with 76 postmenopausal women aged >= 60 years with low (T-score less than -1) lumbar bone mineral density (BMD). The hormone replacement therapy (HRT) group received a low dose of conjugated estrogen (CEE) at a dose of 0.31 mg/day +/- medroxyprogesterone acetate (MPA) 2.5 mg/day. Group HRT/D received the same dose of HRT together with alfacalcidol in a daily dose of 1.0 mu g/day. Changes in lumbar BMD measured by dual energy X-ray absorptiometry (DXA) were followed every 6 months for 2 years. The lumbar BMD of group HRT increased 3.37% [95% confidence interval (CI) 1.6%-5.2%], 4.00% (95%CI 1.6%-6.4%), and 2.32% (95%CI -0.7% to 5.3%) at 12, 18, and 24 months, respectively, when the baseline value was taken as 0%. Lumbar BMD of group HRT/D showed a significant increase beyond 6 months. The percent increases for this group at 6, 12, 18, and 24 months were 6.18 (95%CI 1.3%-6.6%), 6.18% (95%CI 3.9%-8.5%), 7.17% (95%CI 4.3%-10.0%), and 8.75% (95%CI 6.0%-11.5%), respectively. In addition, there was a significant difference in the changes of the lumbar BMD between the two groups at 24 months, suggesting that the combination of HRT and alfacalcidol is more effective than HRT alone in terms of the BMD effect. This study is the first prospective trial demonstrating an additive effect of alfacalcidol on lumbar BMD in postmenopausal women receiving low-dose HRT. It suggests that the combination therapy can be considered to be a promising mode of treatment for bone loss after menopause.