Effect of low-dose alendronate treatment on bone mineral density and bone turnover markers in Chinese postmenopausal women with osteopenia and osteoporosis.

OBJECTIVE: The aim of this study was to evaluate the effect of low-dose alendronate (ALN) treatment on bone mineral density (BMD) and bone turnover markers in Chinese postmenopausal women with osteopenia and osteoporosis.

METHODS: This study was a large-sample, randomized, open-label, prospective, multicenter, clinical trial with a 12-month follow-up. A total of 639 postmenopausal women (aged 62.2 ± 7.0 y) with osteopenia or osteoporosis were randomized into two groups: low-dose ALN (70 mg every two weeks) and standard-dose ALN (70 mg weekly). All patients were also supplemented with calcium (600 mg) and vitamin D3 (125 IU) daily. BMD (measured by dual-energy x-ray absorptiometry; Hologic and Lunar) and levels of serum bone turnover markers (bone resorption marker, carboxy-telopeptide of type I collagen; bone formation marker, alkaline phosphatase) were assessed at baseline and at 3, 6, and 12 months of treatment. BMD and bone turnover markers were compared between the baseline and the end of treatment, and the changes in BMD and bone turnover markers were also compared between the low-dose ALN group and the standard-dose ALN group.

RESULTS: No significant differences in age, years since menopause, body mass index, BMD, 25-hydroxy vitamin D level, and serum biochemical markers were found at baseline between the two dose groups. A total of 558 (87.3%) and 540 (84.5%) women completed the treatment at the 6th and 12th months, respectively. After the 12-month treatment, lumbar spine and hip BMD increased and serum bone turnover markers decreased significantly in both of the treatment groups (P < 0.01), and no differences in percentage changes in BMD at the lumbar spine, femoral neck, and hip were found between the low-dose group (5.60%, 3.87%, and 3.28%, respectively) and the standard-dose group (5.07%, 2.93%, and 3.80%, respectively; P > 0.05). However, levels of serum alkaline phosphatase and carboxy-telopeptide of type I collagen in the standard-dose group decreased moderately compared with those in the low-dose group (P < 0.05 and P < 0.01). The women tolerated the two doses of ALN quite well. Adverse effects were similar in the two groups.

CONCLUSIONS: Treatment with low-dose ALN (70 mg every two weeks) in women with postmenopausal osteopenia or osteoporosis effectively increases lumbar spine and hip BMD, similar to treatment with standard-dose ALN. Low-dose ALN may be a cost-effective and safe protocol for treating osteopenia or osteoporosis in Chinese women.