Effects of Teriparatide and Sequential Minodronate on Lumbar Spine Bone Mineral Density and Microarchitecture in Osteoporosis

The trabecular bone score (TBS) is a new surrogate for trabecular bone microarchitecture assessment, independent of bone mineral density (BMD), calculated from pixel gray-level variations in the lumbar spine (LS) dual-energy X-ray absorptiometry (DXA) image. Although Teriparatide (TPTD) increased LS-BMD as well as TBS in 2 years, the precise time-course of these parameters was not well known. The aim of this study was to determine the changes in LS-BMD and the TBS in osteoporotic patients treated with TPTD, followed by minodronate (MINO). Primary osteoporotic patients with a low LS-BMD (T-score < −2.5) and/or at least one vertebral fracture were treated with TPTD subcutaneously at 20 µg/day for 12–24 months, followed by MINO (orally at 50 mg/once monthly) for 12 months. LS-BMD and the TBS were measured at 0, 3, 6, 12, and 24 months after the initiation of TPTD treatment, and 12 months after the initiation of MINO. The increments of LS-BMD, significant at 6 months, increased until 12 months, whereas the increments of TBS, significant at 3 months (0.035 ± 0.011; p = 0.045 vs. the baseline), stabilized until 12 months. TPTD treatment, followed by 12 months of MINO, maintained both BMD and the TBS. Comparing the increments of the TBS to those of LS-BMD, our results indicate that TPTD treatment improved trabecular microarchitecture faster than mineralization. TPTD treatment, followed by MINO, can maintain both BMD and the TBS.