Comparison of Denosumab and Zoledronic Acid in Postmenopausal Women With Osteoporosis: Bone Mineral Density (BMD) and Trabecular Bone Score (TBS)

BACKGROUND: Denosumab (DEN) and zoledronic acid (ZOL) currently represent the most potent antiresorptive agents for the treatment of osteoporosis. Despite similar effects on bone resorption, these agents have distinct mechanisms of action. The objective of this study was to compare the effect of DEN and ZOL after two-year administration on bone mineral density (BMD), trabecular bone score (TBS), bone turnover markers, and persistence. METHODS: A total of 585 postmenopausal women with osteoporosis who did not use osteoporosis medications were retrospectively reviewed. 290 patients were administered 60 mg DEN subcutaneously every 6 months from 2017 to 2018, and 295 patients were treated with 5 mg ZOL intravenously yearly from 2015 to 2017. BMD, TBS, and C-terminal cross-linking telopeptide of type 1 collagen (CTX) measurements were obtained at baseline and two-year after DEN injection or ZOL infusion. RESULTS: After two-year follow-up, 188 patients in the DEN group and 183 patients in the ZOL group were compared. BMD change from baseline at two years was significantly greater in the DEN group compared with the ZOL group (P < 0.001). The changes of TBS in the DEN group were statistically significant compared with baseline (P < 0.001) and the ZOL group (P < 0.001). The DEN group led to significantly greater reduction of CTX compared with ZOL group (P = 0.041). CONCLUSION: In postmenopausal women with osteoporosis, DEN was associated with greater BMD increase at all measured skeletal sites, greater increase of TBS, and greater inhibition of bone remodeling compared with ZOL.