Effects of alendronate combined with hormone replacement therapy on osteoporotic postmenopausal Chinese women

To evaluate the effect of alendronate combined with hormone replacement therapy (HRT) on postmenopausal osteoporotic Chinese women living in Taiwan, we treated 151 women (age range, 47-70 years; mean, 61 years) with conjugated equine estrogen (0.625 mg), medroxyprogesterone 5 mg, and elemental calcium 500 mg daily with either alendronate 10 mg (n = 79) or placebo (n = 72), and measured their bone mineral density (BMD) at the lumbar spine and hip every 6 months for 3 years. Urine N-telopeptide of type I collagen corrected by concentration of urine creatinine (NTx/Cr) and serum osteocalcin (OC) concentration was also measured at weeks 2, 4, and every 3 months from month 3 for 2 years. Significantly higher percentage increases in BMD at the lumbar spine (P < .0001, 2-way analysis of variance) throughout the 36-month treatment period were found in the alendronate plus HRT group than in the HRT-only group. However, there was no difference in BMD at the femoral neck and trochanter between these 2 groups. Treatment with alendronate plus HRT resulted in a 10.1% increase at the L-spine BMD and a 7.7% increase at the trochanter BMD at the end of the 3-year study period (P < .01, compared with baseline at both sites). A significant decline in urine NTx/Cr was observed at week 4 in the alendronate plus HRT group, whereas in the HRT-only group, a significant decline in urine NTx/Cr occurred at month 9. By the end of 24 months, urine NTx/Cr decreased by 49.7% in the alendronate plus HRT group (P = .001 compared with a 20.4% increase in the HRT group). A significant decline in serum OC level occurred at month 3 in the alendronate plus HRT group, whereas a similar decline was observed at month 6 in the HRT-only group. By the end of 24 months, serum OC decreased by 52.2% in the alendronate plus HRT group (P < .001 compared with a 1.5% increase in the HRT-only group). Subjects treated with alendronate plus HRT had a significantly greater percentage decrease in urine NTx/Cr (P = .0001) and serum OC (P = .0007) than subjects treated with HRT only throughout the 24-month treatment period by 2-way analysis of variance comparison. There was no difference in upper gastrointestinal or drug-related side effects between groups. In conclusion, our data suggest that the use of alendronate combined with HRT for 3 years was well tolerated and it significantly increased BMD at the L-spine and hip in postmenopausal Chinese women with osteoporosis. This regimen is safe and can be used in subjects who have no satisfactory response to a single agent or who have very low BMD with multiple risks. However, this study does not indicate whether HRT plus alendronate has any greater effect on BMD than alendronate alone.