Addition of alendronate to ongoing hormone replacement therapy in the treatment of osteoporosis: A randomized, controlled clinical trial

Alendronate and estrogen are effective therapies for postmenopausal osteopo rosis, but their efficacy and safety as combined therapy are unknown. The o bjective of this study was to evaluate the addition of alendronate to ongoi ng hormone replacement therapy (HRT) in the treatment of postmenopausal wom en with osteoporosis. A total of 428 postmenopausal women with osteoporosis, who had been receivi ng HRT for at least 1 yr, were randomized to receive either alendronate (10 mg/day) or placebo. HRT was continued in both groups. Changes in bone mine ral density (BMD) and biochemical markers of bone turnover were assessed. Compared with HRT alone, at 12 months, alendronate plus HRT produced signif icantly greater increases in BMD of the lumbar spine (3.6% vs. 1.0%, P < 0. 001) and hip trochanter (2.7% vs. 0.5%, P < 0.001); however, the between-gr oup difference in BMD at the femoral neck: was not significant (1.7% vs. 0. 8%, P = 0.072). Biochemical markers of bone turnover (serum bone-specific a lkaline phosphatase and urine N-telopeptide) decreased significantly at 6 a nd 12 months with alendronate plus HRT, and they remained within premenopau sal levels. Addition of alendronate to ongoing HRT was generally well toler ated, with no significant between-group differences in upper gastrointestin al adverse events or fractures. This study demonstrated that, in postmenopausal women with low bone density despite ongoing treatment with estrogen, alendronate added to HRT signific antly increased bone mass at both spine and hip trochanter and was generall y well tolerated.