Effects of Bazedoxifene/Vitamin D Combination Therapy on Serum Vitamin D Levels and Bone Turnover Markers in Postmenopausal Women with Osteopenia: A Randomized Controlled Trial

BACKGROUND: This study aimed to evaluate the effectiveness of bazedoxifene/vitamin D combination therapy in preventing osteoporosis in postmenopausal women with osteopenia. METHODS: This was an open-label, multicenter randomized-controlled, phase 4 clinical trial. Women between ages of 55 and 70 years in 9 medical tertiary centers in Korea were enrolled and assigned into 2 groups: an experiment group and a control group. The experimental group received bazedoxifene 20 mg/vitamin D 800 IU tablets for 6 months, and the control group received calcium 100 mg/vitamin D 1,000 IU tablets for 6 months. RESULTS: A total of 142 patients (70 in the experimental group and 72 in the control group) were included. The least-square mean±standard error of change in propeptide of type I collagen after 3 months was −6.87±2.56% in the experimental group and 1.22±2.54% in the control group. After 6 months, it was −21.07±2.75% in the experimental group and 1.26±2.71% in the control group. The difference between the 2 groups was −22.33% (P<0.01). The change of C-terminal telopeptide was −12.55±4.05% in the experimental group and 11.02±4.03% in the control group after 3 months. It was −22.0±3.95% and 10.20±3.89, respectively, after 6 months. The difference between the 2 groups was −32.21% (P<0.01) after 6 months. There was no significant difference in adverse events between the 2 groups. CONCLUSIONS: The osteoporosis preventive effect and safety of administering bazedoxifene/vitamin D combination pill were confirmed in postmenopausal women who needed osteoporosis prevention.