Comparison of Bone Mineral Density and Markers of Bone Turnover in Osteoporotic Women after 6-Month Treatment with Alendronate or Bazedoxifene: A Randomized Controlled Trial

BACKGROUND In a randomized controlled trial, we compared the bone mineral densities (BMDs) and blood markers of bone turnover during short-term treatment of osteoporotic women with bisphosphonate alendronate or bazedoxifene, a selective estrogen receptor modulator. METHODS Ten and eleven patients were randomized to the alendronate and bazedoxifene groups, respectively. BMDs were measured before and after 6 months of treatment. Blood tests were used to measure the levels of osteocalcin (OC), C-terminal telopeptide of type I collagen (CTX), vitamin D3, and parathyroid hormone pretreatment and after 3 and 6 months of treatment. The variables were compared statistically. RESULTS The alendronate group showed decreases in blood levels of both OC and CTX during the study period (P<0.001 and P=0.002, respectively), while the bazedoxifene group had a decrease only in OC levels (P=0.012). After 6 months of treatment, BMDs significantly increased in the alendronate group at multiple bone sites, including the L1-4 lumbar vertebrae, femur trochanter, and total femur. However, there was no significant increase in BMD in the bazedoxifene group. BMDs were not significantly different between the 2 groups. CONCLUSIONS Patients treated with alendronate showed more rapid suppression of markers of bone turnover and higher BMD than those treated with bazedoxifene during a short-term regime. Considering the effects and complications of each medication, the relationship between bone turnover rate and bone quality will need to be investigated in future studies.